As for Plasma Focus - this is essentially a magneto-plasmadynamic (MPD) device, and it operates in a pulsed mode. I have reviewed information provided by http://focusfusion.org and found claims to be highly questionable. MPD's also suffer from elctrode erosion and contamination of the plasma.There are a number of unsolved, and possibly unsolvable, problem with the electrodes in a fusor power system. To begin with, the electrodes cannot influence the potential within themselves, so that the fusion plasma will be in more or less direct contact with the the inner electrode, resulting in contamination of the plasma and destruction of the electrode. Also, the transparency of the electrode will have to be unbelievably good since an ion will have to pass through it on the order of 1010 times before undergoing a fusion reaction.