Stellarator vs. Tokamak

Two types of experimental nuclear fusion reactor. Both use magnets to try to keep hydrogen isotopes deuterium and tritium under enough temperature and pressure to fuse their nuclei into helium, but, said the Frankfurter Allgemeine, the tokamak system can only work in pulsed operation while the less common stellarator can do continuous operation, making it useful for research into electricity-generating applications.

Physicists say the bigger a pulsing tokamak is, the better it works. The world’s largest tokamak experimental fusion reactor is under construction in southern France. The “Iter” reactor in Cadarache is a joint project of Europe, Japan, Russia, China, South Korea, India and the U.S., originally budgeted at 4.6 billion euros with completion in 2020 but now expected to cost ~15 billion and be at least two years late. A project manager said the extra costs are because the original estimates were only for construction costs and did not include e.g. insurance, manufacturers’ profit and administration costs. Because each of the seven partners wants to acquire all knowledge related to this reactor so they can build copies at home, many of the parts have been manufactured in factories in multiple countries instead of by one contractor, with the added risks this entails.

The world’s largest stellarator experimental fusion reactor officially completed construction this month in Greifswald, Germany. The Max Planck Institute said since 1995 construction of the “Wendelstein 7-X” has been financed by approx. 201 million euros from the E.U.’s Euratom program, 672 million from Germany and 131 million from the state of Mecklenburg-Vorpommern; it was originally budgeted at 500 million euros but ended up costing >1 billion.

The stellarator in Greifswald is not intended to fuse hydrogen atoms but is intended to research electricity generation via fusion. The tokamak in Cadarache intends to use 50 megawatts to produce 500 megawatts via fusion, getting more energy out than was put in for the first time said a representative; researchers there are interested in pure physics research but also developing technologies that will be used in the next generation of fusion reactors, probably not available before 2050.

The world’s previous largest tokamak experimental fusion reactor was at Culham, U.K., and only managed to produce 60% of the energy that it fed into the reaction.

Physikgesäubert vs. chemiegesäubert

“Cleaned by physics vs. cleaned by chemistry.” In the late 1990’s, to this tourist, it appeared that U.S. appliances were designed so that ever-more-sophisticated soaps and/or soap marketing would get laundry clean, while German appliances were designed to use physics to get laundry clean. The latter had gotten so good at it that for years they’d been competing by promising not cleaner clothes but to reduce the electricity and especially water required to do a load of wash.

The fabrics in clothing sold in 1990’s Germany were much higher quality than the kleenex clothes sold in the U.S.A.: thicker, stronger, less likely to wrinkle. At the time I thought this was because German consumers complained before purchases more, both to each other and to the stores*, but perhaps it was also due to post-purchase complaining after clothes designed to be worn twice and soap-laundered dissatisfied chatty consumers rather egregiously when worn four times and agitation-laundered.

In both countries, water in rural creeks and rivers formed persistent foam that did look like soap bubbles, originally white but turning yellow with dust as it was carried downstream. But friends said this was caused not by household soaps but by artificial fertilizers in runoff from farmers’ fields.

(Fizz EEK geh ZOY bat   vair seuss   chhem EE geh ZOY bat.)

*   “Are you trying to verarsch me with that see-through, pilly, short-fiber cotton?”

Wabern

Billow, waft, swirl. Onomatopoeiatically, this word sounds like how waves might propagate through a swimming pool filled with jello, suspended cornstarch or Amish apple butter, but apparently it’s used more for the lighter ethers, airs and vapors, tendrils of fog or smoke. Süddeutsche.de talked charmingly about rumors that wabern durch Bayern, waft through Bavaria.

(VOB urn   do rrchh   BUY urn.)

Schwappen

To slosh, swash. Topic of a recent Ig-Nobel Fluid Dynamics prize for a paper entitled “Walking With Coffee: Why Does It Spill?”

(SHVOP en.)

Blog at WordPress.com.