I’m still curious about glassy metals. Unlike crystalline metals, the atoms are arranged haphazard like rocks in a rockpile. Perhaps some type of glassy metal .... or an alloy of two or more metals in a glassy form .... might make for more resilient electrodes that endure the punishment in such a hellish environment. Such metals are known to have some interesting properties. For example, razor blades of glassy metal that don’t get dull when you shave with them.

  Can anybody give me some feedback about how long some kind of glassy metal / metal(s)  might last in a FF reactor .... without much wearing away of electrodes ? And what about other desirable properties, such as electrical conductivity, high temperature, resistance to intense X - rays, and etc. ?

  I know that beryllium alloyed with copper makes non - sparking electrical contacts. I wonder how well a glassy metal version of it might hold - up in the FF. Or perhaps some tungsten could be alloyed with a glassy metal to add more strength also. All of these things would require lots of real world experimentation in glassy metallurgy to determine and figure out what works the best.

There is a dimple in the end of the center electrode. The optimal shape of it remains to be determined.  It has to be there in order for the plasma filaments to fountain together.  The plasmoid actually forms slightly below the end of the electrode down in this dimple. 

This is why x-ray transparency is so important for this electrode.  The the x-ray absorption of elements gets large really quick as you work your way up the periodic table.

what’s the actual recyclability of the beryllium anode?

if 1 anode = 1 kg beryllium, and if focus fusion must consume beryllium,
essentially destroying it through wear by the odd neutron,
such that the anode cannot be refurbished,
then consuming 250 t/year beryllium supports only about 250 GW energy production:

250,000 kg / 1 kg per anode = 250,000 anodes
/ 12 anode replacements per year x 12 MW per reactor
= 250 GW

Overall global beryllium resource estimates are thought to be approximately 80,000 tons with the Americas, Central Africa and Eastern Europe having the most concentrated and economically viable deposits.
—http://www.ibcadvancedalloys.com/s/AboutBeryllium.asp

at 250 t/y, this would yield 320 years; but as of 2010,
global consumption of beryllium is now already 620 t/y.

80,000/620     = 129y to gone
80,000/(620+250)=  92y to gone

we must plan to search for more beryllium, on other planets and asteroids

I think the recylability will be near 100%. The metal vaporized from the anode will not really go very far. It will redeposit as a coating when the machine shuts down to change the anode.  Eventually that build-up will have to be removed with a solvent, maybe once every few years or so.  The electrodes themsleves will just be melted down and reformed. Induced radioactivity will be negligible, even after many re-uses. (It is all in the impurities anyway.)

In fact, with super-cheap electricity powering plasma torches, pretty much everything we throw out will get recycled at high temperature.

That makes me more comfortable.

at, say 97.5% recovery, (assuming 1 kg per anode), then:
for focus fusion to meet Weinberg’s “age of substitutability”, of ~60 TW globally, or ~7 kW per person,
( http://books.google.ca/books?id=ZaxLsdJ_ABEC )

then only ~ 5000 t beryllium will be needed, replenishing with 125 t/y from ores and other recycling.

descendants will still want to explore the solar system for additional beryllium. but they’ll have more time.

With plenty of cheap energy we might explore the element transmutation option more thoroughly

Breakable - 21 April 2010 04:50 PM

With plenty of cheap energy we might explore the element transmutation option more thoroughly

There’s a problem with that, though. We might expect to make beryllium from lithium-9, through beta decay, (~50%yield), but lithium-9 is hard to obtain, since lithium-8 is unstable with half-life ~800ms. So you’ll need an intense, and highly focused neutron beam to double-bump lithium-7 nuclei, hoping they don’t fission in the process. the yield will be low (which explains why beryllium is rare, here on earth, anyway).

I would say that i’m more interested in seeing them use superconductors like the one made by Chang-Beom Eom at UW-Madison, it doesn’t sound like they are using the right elements to have x-ray transparency that you would want but there ability to carry current and probability resist melting.
http://www.physorg.com/news186667839.html

Lerner - 21 April 2010 06:23 AM

I think the recylability will be near 100%. The metal vaporized from the anode will not really go very far. It will redeposit as a coating when the machine shuts down to change the anode.  Eventually that build-up will have to be removed with a solvent, maybe once every few years or so.  The electrodes themsleves will just be melted down and reformed. Induced radioactivity will be negligible, even after many re-uses. (It is all in the impurities anyway.)

In fact, with super-cheap electricity powering plasma torches, pretty much everything we throw out will get recycled at high temperature.

Do you foresee any issues with metal vaporized from the anode interfering with the subsequent pinches when running at full speed?  I assume that the odds on generating any radioactive byproducts from the vaporized anode are very low.

As an aside- if I had $50k to invest, I would (I bet that you have heard that quite a bit).