When any hydride including pure deuterium and protium or any metal is compressed by pressures in the order of millions of atmospheres within the depths of most celestial bodies, these materials will initiate and support the LENR reaction. This natural reaction will extract heat from the vacuum.
This quantum mechanical reaction will produce superconductivity and super-fluidity up to a temperature of 90,000 F. This is why Rossi can support a LENR reaction based on ultra dense hydrogen in his ballerina plasma.
Sometimes, research in main stream science can inform how LENR works.
Breakdown of Fermi degeneracy in the simplest liquid metal
This research into ultra-dense deuterium is revealing in the way the LENR active agent behaves when used at extreme temperatures and pressures in a plasma.
Compressed hydrogen enters a metalized quantum mechanical state that is preserved through extremely high temperatures and pressures. This behavior most likely includes superconductivity even at extreme temperatures.
In detail, during the compression produced through the use of an optical shockwave, the deuterium's optical properties is maintained up to a minimum temperature of 90,000 degrees Fahrenheit whereupon as temperatures increase beyond this point, its quantum nature begins to deteriorate.
The reflectivity of the hydrogen quantum fluid is the mechanism used by this experiment whereby the polaritons can form the LENR active plasmoid structure in the electron quantum layer covering the positive core of the ultra dense material. The polaritons form within the optical mirror that the coherent quantum nature of the deuterium generates.
Above 90,000 degrees Fahrenheit, this LENR active behavior begins to deteriorate. The polariton cover begins to weaken.
One important implication of this behavior is that any metal that is highly compressed will support the LENR reaction. For instance, in the Proton 21 experiment, copper demonstrates LENR activity when highly compressed through the use of a shock-wave that compresses the copper by the initiation of a powerful electric arc.