Good question, Tulse. I don’t remember seeing a similar thread. I’d guess that the capacitor would be the limiting factor. From Google:

Electrolytic capacitor – Wikipedia, the free encyclopedia
The ancestor of the modern electrolytic capacitor was patented by Julius Lilienfeld in 1926. Lilienfeld’s design resembled that of a silver mica capacitor, …
en.wikipedia.org/wiki/Electrolytic_capacitor

If you just go back as far as when Filioppov (1961-62) & Mather (1964) came up with the DPF, then if more effort was made into researching them at the time would have meant when progress in understanding plasma phenomena in general was made in the 70s then the DPF would have been better placed to attract funding alongside tokamak projects built in the 80s.

Someone could have come up with the DPF concept before Filioppov & Mather, but not much before. I would say the earliest one could have been built would be maybe 10 years before, but not much more than that – say 1950.

Having said that, I think the whole range of technologies needed to get power from fusion in a DPF mean it could not have been done much before where we are today, maybe 10-15years ago at best.

If you just take for example the turbomolecular pump, developed in 1958. Or from the nuclear viewpoint the various collision cross sections for different elements worked on as a result of the development of the H-Bomb.

It wasn’t until 1941 when Kolmogorov first developed his theories of turbulence, that were later applied to magnetic plasmas that any kind of hypotheses of how macroscopic forces cascaded the energy transport down to smaller scales was considered.

boron trifluoride is a precursor to the boranes.

“Boron trifluoride was discovered in 1808 by Joseph Louis Gay-Lussac and Louis Jacques Thénard, who were trying to isolate “fluoric acid” (i.e. hydrofluoric acid) by combining calcium fluoride with vitrified boric acid; the resulting vapours failed to etch glass, so they named it fluoboric gas.”

capture of the exit beam is a significant step. the Rogowski coil is dated circa late 19th to early 20th century.

The onion is completely new science, probably requiring photonic band gap semiconductors. In absense of this, a heat engine would convert energy.
“The Tesla turbine is a bladeless centripetal flow turbine patented by Nikola Tesla in 1913.”

Brian H wrote:

In October 1745, Ewald Georg von Kleist of Pomerania in Germany found that charge could be stored by connecting a high voltage electrostatic generator by a wire to a volume of water in a hand-held glass jar

So you just need a bigger jar.

Switching and discharge within a few 10s of ns? I doooonn’t thang sew! :grrr: :bug:

that depends on the size of the wire. if 50 ns is the needed rise time (= 1/2 wave, ie: 10MHz), and you can tolerate a .006 ohm resistance, the skin effect limits the wire dimensions (in copper, ρ = R·Area / length = 1.68×10^−8 Ω·m; skin depth= 20.5 μm @10MHz) to a length no more than 7.2 x the circumference.

“The effect was first described in a paper by Horace Lamb in 1883 for the case of spherical conductors, and was generalised to conductors of any shape by Oliver Heaviside in 1885.”

vansig wrote:
without electrolytic capacitors, a glass ceramic capacitor array, of 129uF @ 50 kV, would fit onto a spherical shell, 5m average radius and 1.5 m thick (assuming 100 plates, spaced 15mm apart). The reactor would be, easily, as big as a house.

… but this would solve the caps lifespan issue, right? 🙂

Eric, could the switches have been made adequate then? That seems still to be a choke-point.