This is a "farnsworth" reactor they've been about for about 50 years or so.
Problem is in scaling. You can never produce uasble amounts of energy from one for various reasons.
Firstly you have no magnetic confinement so as your ion beam increases it will disperse and the whole thing will become unstable , secondly we are talking of millions of degrees kelvin here as the ion bem increases the target will simply melt or vaporise.
http://www.guardian.co.uk/science/2003/sep/25/ science.highereducation
This is no amazing amateur breakthrough but well known science and from a fusion perspective a dead end.