"Critical mass" is a broader concept than its familiar usage in nuclear fission. In that context, CM relates to neutron multiplication past a threshold level - but the concept is qualitatively more than just a subset of "positive feedback."
There are also other contexts for critical mass, in the field of socio-dynamics - such as is inherent in the "paradigm shift," "the hundredth monkey," the "bandwagon effect," the "tipping point," the viral video, and of course, the "meme" and "morphic field" of Sheldrake. But wait. (best Bob Mays accent): there's more. As mentioned yesterday, in the case of quantum mechanics, there can also be a "critical mass" equivalent which describes some or even all of the prior runaway reactions of LENR. It is not a thermal property per se, although heat is an obvious side effect. There are in fact, a number of scientific papers on "entanglement mass" which would be the corollary in QM to critical mass. I have a feeling that there are vorticians who have studied this niche of QM thoroughly and can cite a relevant paper or two. and perhaps speculate on the parameters which would promote entanglement. For Jack's upcoming pressure cooker experiment :-) the parameter which would promote quantum entanglement could include 1) Magnetic field (put a big sacrificial magnet in the cooker 2) Low temp - freezer storage and a dry ice bath could help 3) Ageing (leave that magnet in the cold powder for a week before the experiment). Do not use deuterium ! and "duck and cover". (which was itself a meme from an earlier era)
