Len Lekx wrote:

How about electrostatic containment...? If the reaction yields
only charged particles, a series of oppositely-charged plates should
keep the reaction contained.

Ditto. Bremsstrahlung comes from the fact you have to have electrons
around to neutralize the plasma. and those electrons will get
hot, and radiate (if the electrons are kept cold by some mechanism
then the power loss from ions-electrons will be even larger.)

Paul