Hall thruster

When last we were looking at high-impulse engines (sacrificing thrust), we were looking at the Ebrahimi Alfvén plasma torch. This came out of Princeton's fusion works. Princeton also owns a lab for actual thrusters; last night they announced progress on the Hall design.

DEFINITION 4/18/22: Lou Grims.

As intimated last weekend, it's all well and good to have a high energy process, but if your chassis melts or even reacts with the plasma, you don't have an engine; you might even have a bomb. Best is not to have a chassis at all, as such. These are possible because, hey, ions can be channelled with magnets; in practice, the plume widens at exit. I hadn't known we cared after the plume was out of the tube but, apparently, we care.

Princeton propose a segmented (concentrically joined) electrode. The propellant they've chosen is xenon. For that, the application will be the smaller satellites, "cube sats".

I am curious: does it scale to Ebrahimi's design; can it focus ionised helium from a fusion drive? 'Tis possible both designs already blast the plasma so fast outward there's not much value in focusing the plume further. And with the latter, they'd like to deal with the neutrons before getting into ions.