From: Teslaalset
Why would Rossi not put SiC powder in the inner cylinder instead?
Plasmons apparently form polaritons most readily at the interface between a
metal surface and an insulator . but not so readily on a ceramic powder
itself (without metal contact) - so one interpretation of that requirement
is that having two surfaces which are very close together like nested tubes
- is helpful for this outcome when one is metal and the other is ceramic.
But the short answer is that Rossi was probably aware, as he was increasing
the temperature in his testing - that his steel cylinder was sagging at high
temperature (or failing) and he needed the support of a high temperature
ceramic. He may have been lucky with the choice of SiC, or else he, or
someone on his staff has great insight.
IOW - Rossi may not have known of the incredibly steep peak of reflectance
for SiC at 10 microns, leading to superradiance - but he was fortunate to be
in a particular Italian Lab (with Focardi) where SiC is routinely used, so
it was available - and he quickly found that it worked very well.
