Talk-Polywell.org

So I am having visions of a Polywell ala the space-time portal in Contact...

I tried to tell them this 15 years ago .... should have seen the looks of derision targeted at a "mere" hydro-dynamicist.

SImply, axial fluid flow through a curved pipe is unstable to the first order without a bulk transverse rotation. A torus (tokomak) is basically a curved pipe.

It has taken them 40 years to figure this out, whoop-dee-do.

icarus wrote:I tried to tell them this 15 years ago .... should have seen the looks of derision targeted at a "mere" hydro-dynamicist.

SImply, axial fluid flow through a curved pipe is unstable to the first order without a bulk transverse rotation. A torus (tokomak) is basically a curved pipe.

It has taken them 40 years to figure this out, whoop-dee-do.

There was some discussion here a long time ago (in internet years) about a rotating AC field superimposed on the Polywell DC field for POPS. It wouldn't be hard to do. Useful? Well that was conjecture.

Slough and Co. have also used rotating fields for FRCs:
AN OVERVIEW OF THE STAR THRUST EXPERIMENT

DeltaV wrote:Slough and Co. have also used rotating fields for FRCs:
AN OVERVIEW OF THE STAR THRUST EXPERIMENT

If they are using IGBTs the coils are shock excited (500 KHz desired freq.). Thus they get another advantage out of a high Q setup.

Yeah, Sloughs work is among my favorites.

Let me revise and extend my remarks. IGBT switching is limited to about 50KHz for the usual devices and can be pushed to about 100 KHz with higher losses (caused by slow turn off of the intrinsic bipolar). So if they are using IGBTs they are sub-harmonically exciting their set up and using the high Q to maintain the current between power pulses.

icarus wrote:I tried to tell them this 15 years ago .... should have seen the looks of derision targeted at a "mere" hydro-dynamicist.

SImply, axial fluid flow through a curved pipe is unstable to the first order without a bulk transverse rotation. A torus (tokomak) is basically a curved pipe.

It has taken them 40 years to figure this out, whoop-dee-do.

Magnetohydrodynamics has only been around for 40 years... ?????

Robthebob wrote:

icarus wrote:I tried to tell them this 15 years ago .... should have seen the looks of derision targeted at a "mere" hydro-dynamicist.

SImply, axial fluid flow through a curved pipe is unstable to the first order without a bulk transverse rotation. A torus (tokomak) is basically a curved pipe.

It has taken them 40 years to figure this out, whoop-dee-do.

Magnetohydrodynamics has only been around for 40 years... ?????

Actually, I think he is referenceing an ~40 year timeframe for functional tokamaks.

Wikipedia wrote:The group constructed the first tokamaks, the most successful being T-3 and its larger version T-4. T-4 was tested in 1968 in Novosibirsk, conducting the first ever quasistationary thermonuclear fusion reaction.[3]