Not really relevant to the question,but I just got thinking about energy and temperature. Temperature is a measure of the average kinetic energy of a particle in an ensemble, and it occurred to me that the electron volt was a fine way to measure particle energies -- and I had no idea of how hot a gas with average particle energies of 1 eV was. So I looked it up. 1 eV is about 11,600 degrees Kelvin.So the energies that Warren is talking about here are what you'd expect from temperatures of about half a trillion to 1 quadrillion degrees. Returning to the point: perhaps the low-energy processes are simply scooping up ambient charged particles and accelerating them; the preponderance of electrons at those energies can be explained by the fact that electrons vastly outnumber positrons. Then, at higher energies, perhaps we are just looking at the product of pair-creation. Processes at energies above about 1 MeV (rest mass of a positron-electron pair) will produce positrons and electrons in equal numbers. On Wed, Mar 11, 2015 at 5:11 PM, Warren D Smith <warren.wds@gmail.com> wrote:
http://physics.aps.org/articles/v6/40
Some cosmic rays are electrons, some are positrons, and some are other things. Focusing only on the first two, the AMS experiment in the space station finds that the ratio of positrons to electrons depends upon the ray-energy. ENERGY positron fraction 0.5 GeV 0.095 to 0.11 7 GeV 0.02 (min) 100 GeV 0.11 to 0.15 300 GeV 0.15
Why? These energies seem too large to be explained directly by any set of nuclear reactions. There must be cosmic accelerators out there producing these hotties, which makes it mysterious why the positron fraction should depend in this funny way upon energy. Another speculation is that somehow these are coming from hypothetical superheavy "dark matter" particles, in which case this is telling us that their masses ought to be within this energy range.
-- Warren D. Smith http://RangeVoting.org <-- add your endorsement (by clicking "endorse" as 1st step)
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