Reply To: Energy Policy in Chile – Economist Article

[markus7]

TimS wrote: I see nothing about a source of magnetic force in this article, but the description starts by saying that a very strong electric force is created when the laser drives electrons off the foil, which is next to the boron film. The electric force would be in the correct direction to drive the alphas. Would this force be strong enough to reverse the path of high speed alphas heading toward it? Apparently it is strong enough to strip protons from metal nuclei… (is this really what is meant?)

Also, given the second to last paragraph of the article, it does not sound like Chapman has missed these problems:

The NASA engineer acknowledges that this collection of ideas is still a long way from being a practical device. For example, losses from the alpha particles striking the walls of the exhaust nozzle or each other lower the net power output. [em]Figuring out how to control the particles’ path is an important consideration.[/em]

The initial “very strong electric force .. created when the laser drives electrons off the foil” is sufficient for generating, it is claimed, 163Kev protons. The alpha particles are 2.5 to 3.8 Mev (see second figure). No, I don’t see any way that any electric field generated by the initial light pulse could be strong enough to deflect the alphas in the thrust direction.

Remember that almost half these alphas will be moving in the wrong direction. Electric fields totaling million of volts would be needed to get them to go the ‘right’ direction.

This does not look like a detail to be worked out, but as an obvious, irrecoverable fatal flaw.