Unclesyd,
While I've seen the 30,000
oC number cited on several websites too (most of them mis-spelling Odeillo also), my enjuneer sense tingled when I saw that. Above 10,000
oC and we enter the plasma physics realm, where gases like N
2 and O
2 are fully dissociated, may begin to ionize, and temperature becomes a somewhat vague term.
From MS-Encarta entry for solar energy, on this link:
the following excerpt comes:
"One important high-temperature application of concentrators is solar furnaces. The largest of these, located at Odeillo in the Pyrenees Mountains of France, uses 63 mirrors with a total area of approximately 2,835 sq m (about 30,515 sq ft) to produce temperatures as high as 3200°C (5800°F). Such furnaces are ideal for research requiring high temperatures and contaminant-free environments—for example, materials research to determine how substances will react when exposed to extremely high temperatures. Other methods of reaching such temperatures usually require chemical reactants that would also react with the substances to be studied, skewing the results."
There's also a link to the Odeillo website, but I can't get much from it, not being much of a French speaker. The link is here:
5800 °F is still nothing to sneeze at - it is a respectable fraction (90%?) of the thermal solar surface "temperature" (itself a somewhat fuzzy term, and varies depending upon what source you cite). Odeillo's maximum is probably limited to the 5800 °F value more by the fact that almost all known materials will be molten or vaporized at this temperature ("um, M'sr. professor, our probes keep melting, what should we do?...).
