Ahern is correct in stating that the "magic" particle size is very small; 3 to 15 nanometers in diameter. This type of particle is the business end of the reaction in the same way the sharp tip of an electrode is where the energy of a spark is concentrated and amplified.
But other size particles are required to get magnetic field strength up. The particle size produce by low melting point metals also must be supplied in the size particle mix. This is what Rossi is producing with his secret sauce addition. Yes, he adds a low melting point alkali metal to his reaction as a power amplifier. This type particle acts as a step up transformer coil where power is concentrated into a high voltage capacitive discharge. But the most important particle size is the 5 micron particle covered with nano hair. This particle is the power house of the reaction. This particle provides the receiving antenna for the SPP pumping generated from the "mouse" component of the reactor. You can think of this large particle as the "Cat". The Mouse produces dipole oscillations in the large body of this jumbo particle where the SPP are born. The power produced by this huge particle is feed down the nano-hair covering to their sharp tips at tremendous power amplification. This dipole power produced in this micro particle feeds the step up power amplification process that occurs in the smaller diameter particle assemblages down the particle size chain to those magic 2 nanometer particles. Ahern does not understand this power concentration system and has only seen limited magnetic power produce by his particles because of this lack of this understanding.
