Talk-Polywell.org

D Tibbets wrote: Structures like struts are magnetically shielded and perhaps also electrostatically shielded

Magnetic shielding of struts is difficult at the interface with the magnets.

Electrostatic shielding looks easy if you're dealing with a single particle species, but is practically impossible with a near neutral plasma approaching the struts. A potential well confining ions helps a lot here.

hanelyp wrote:

D Tibbets wrote: Structures like struts are magnetically shielded and perhaps also electrostatically shielded

Magnetic shielding of struts is difficult at the interface with the magnets.

Electrostatic shielding looks easy if you're dealing with a single particle species, but is practically impossible with a near neutral plasma approaching the struts. A potential well confining ions helps a lot here.

Electrostatically shielded struts against ions with magnetic shielding against electrons- sort of like the Polywell, except outside the magnets .Never said it would be easy. Keep in mind that in the neutral plasma Lockheed design the ions are magnetically confined at high Beta. The number of passes may be up to several hundred less than the electrons, but this would still be perhaps as much as 1000 passes. As such the internal high Beta confined ions may be several orders of magnitude more dense than the ions recirculating between cusps. As such the shielding needed/ external ion impacts will be much less relative to the internal fusion producing ion density. This may allow for tolerable losses of the recirculating ions (and electrons ) to structures without fatally poisoning the system. Having said this, it seems EMC2 has already buttedup against plasma poisoning with high Z contaminates. Dr Krall mentioned early work where doubling the input power poisoned the system - due to structure impacts/ contamination leading to loss of the potential well. It seems (reading between the lines) that this may also have happened in WB8. Extensive efforts to shield external structures may be necessary for either approach.

Dan Tibbets

A little news in this article (May this year):

http://i-hls.com/2016/05/lockheed-marti ... generator/

• Lockheed is “about four months into a little bit more significant investment” into the technology
• “Basically at this stage we are increasing the temperature at which the fusion could occur, and our process for containing the reaction, and we will continue to elevate the level of the temperature and testing the containment theory,” said Weiss.
• "Weiss also confirmed the team has achieved “initial plasma,” an important early step for the reactor."

"Initial Plasma?" Durn, a high school kid can do that with a fusor running on a neon sign transformer and a couple of diodes.

Wanna come by and see mine run?

And then the kid gets a decent power supply an some D2 and joins the neutron club. Which they also have not described achieving. Been there, done that.

When they have to build an earth berm around the thing to shield against all the neutrons, then they're getting somewhere. If EMC2 can get some backing for the next stage of work, they may be at that point.

I resisted disparaging the significance of first plasma, but as T. Ligon said, it is trivial. It has little to do with the physics that you are pursuing. It is a trouble shooting step that merely means you have plugged the cord into the wall and managed to avoid blowing all of the fuses or burning the building down. Plasma production is stupendously easy to create. Any florescent light bulb does it, as does sneaking up behind some one on a winter day, shuffling you feet on a carpet, and grinning as you extend your finger towards your victum/ err... I mean your friend.

Dan Tibbets

Yep. The article's words, not mine. Well, at least it means they're doing more than simulations now, which I didn't know.

Simulations are much cheaper than hardware. Hardware can tell you if your simulations are any good.

Just as the term "maiden voyage" has little meaning without reference to a specific vessel or vessel class, the term "first plasma" has little meaning without reference to a specific reactor design. We've already seen plasma in a Lockheed-Martin reactor more than three years ago, so presumably the article is referring to a more recent design, although it is very sparse on details.