mvanwink5 wrote:You could synchronize firing a laser to ionize the pellet at the right place. Just a thought.
sounds like an excellent idea to me. i would think "the right place" would be at the point inside the wiffleball boundary where the ions will have just enough momentum to be reflect just at the edge of the electrostatic well, with a safe margin. sort of like shuffle-ball.
Change laser to Maser (microwaves) and you are describing efforts already tried, or at least contemplated. Microwaves can magnify the ionization rates.
Using the Z- pinch example. I could see dropping a pellet into the machine and then zapping it to vaporize it. The question then becomes how much of the produced gas is ionized by the by the zapping. If a significant portion remained neutral gas, it would probably have higher velocities than a puff of cold gas, and the edge ionization would suffer. Alternatly, if the zapping created a cloud of hot ions, that would defeat the purpose of havig low energy ions at the Wiffleball edge.
With capacitors. Thy may have had sufficient power (~1.5 to 2.5 MW)but only till the capacitors drained- end of test.
I thought they were all pulsed until now anyway?
Pulsing is relative. Bussard was happy to get ~ 0.25 seconds of operation as that was enough to prove most of the physics. But it left some questions. Longer 'pulses' would have given better information about ion thermalization times, and possibly other issues. Pulses of ~ 10-100 ms (with appropriate diagnostics- another problem WB 6 had) would have disarmed critics on issues of thermalization, confluence(?), etc. The neutron signal would be less noisy, x- ray measurements would be easier, and thus possibly addressed some of the Bremsstrulung issues, etc, etc.
Steady state (like minutes to years ) are necessary more for engineering issues and production issues, not physics issues.. This is in contrast to DPF which is definitely a pulsed machine. The Polywell is definitely a steady state machine, just the definition of the steady state period that is possible or needed is in question. Steady state conditions may be obtained and maintained for only 20 milliseconds and be repeated 100 times a second in a production plant. Whether you call this a pulsed machine or a steady state machine is a matter of semantics. Even stars could be considered as steady state of pulsed (especially pulsating of flare stars, repeating nova, etc.) machines, depending on how you set up your definitions. You could even apply pulsation behavior around a steady state mean. POPS may fit into this definition.
mvanwink5 wrote:You could synchronize firing a laser to ionize the pellet at the right place. Just a thought.
sounds like an excellent idea to me. i would think "the right place" would be at the point inside the wiffleball boundary where the ions will have just enough momentum to be reflect just at the edge of the electrostatic well, with a safe margin. sort of like shuffle-ball.
Change laser to Maser (microwaves) and you are describing efforts already tried, or at least contemplated. Microwaves can magnify the ionization rates.
Using the Z- pinch example. I could see dropping a pellet into the machine and then zapping it to vaporize it. The question then becomes how much of the produced gas is ionized by the by the zapping. If a significant portion remained neutral gas, it would probably have higher velocities than a puff of cold gas, and the edge ionization would suffer. Alternatly, if the zapping created a cloud of hot ions, that would defeat the purpose of havig low energy ions at the Wiffleball edge.
Dan Tibbets
you dont have to zap it at the wb edge. you can zap it anywhere inside the wb you need to to make the ion energies turn out right. the electrons will just scatter and diffuse inside the wb in a nanosecond. their mass is almost 4 orders of magnitude less so their inertia is negligible and their magnetic field interaction is totally dominant.
As I am asleep at the wheel, I did not catch this until now...
Date Signed (mm/dd/yyyy) : 12/20/2011
Effective Date (mm/dd/yyyy) : 12/20/2011
Completion Date (mm/dd/yyyy) : 09/30/2012
Est. Ultimate Completion Date (mm/dd/yyyy) : 03/31/2014
But of note, is that the money did not change (on this), just the target dates.
The development of atomic power, though it could confer unimaginable blessings on mankind, is something that is dreaded by the owners of coal mines and oil wells. (Hazlitt)
What I want to do is to look up C. . . . I call him the Forgotten Man. (Sumner)
Any idea what it means? I'm guessing it means testing on WB 8.0 is currently scheduled to be concluded by September 30th of this year, with optional testing of WB 8.1 to be completed by March 31st, 2014. I don't see any more advanced device being approved without additional funding.
Temperature, density, confinement time: pick any two.
IIRC WB-6 had around 1MW input as well. I remember looking at this when we were trying to figure out what favorable loss scaling would look like in WB-8. It's important to remember how losses (inputs) are supposed to scale -- at B^.25 * r ^2, the input to even a 1.5M reactor is only an order of magnitude or so more than WB-6/7, the confinement and power density (output) just gets way, way better.
It sounds like they saw more maxwellianization than expected, since they're talking about well depths (and of course there was always some doubt about the claimed annealing). I would characterize this as "meh" -- mildly disappointing. The Polywell probably lives or dies on the high-beta confinement question, as Rick's ITER comparison tended to argue.
n*kBolt*Te = B**2/(2*mu0) and B^.25 loss scaling? Or not so much? Hopefully we'll know soon...
TallDave wrote:It sounds like they saw more maxwellianization than expected, since they're talking about well depths (and of course there was always some doubt about the claimed annealing). I would characterize this as "meh" -- mildly disappointing. The Polywell probably lives or dies on the high-beta confinement question, as Rick's ITER comparison tended to argue.
Did I miss something? What implied this? Thanks
Best regards
Counting the days to commercial fusion. It is not that long now.
(and of course there was always some doubt about the claimed annealing).
The IAC paper would seem to take it past claimed, and make it an observed. (from page 7)
Ions spend less than 1/1000 of their lifetime in the dense, high energy but low cross-section core region, and the ratio of Coulomb energy exchange cross-section to fusion cross section is much less than this, thus thermalization (Maxwellianization) can not occur during a single pass of ions through the core. While some up- and down- scattering does occur in such a single pass, this is so small that edge region collisionality (where the ions are dense and “cold“) anneals this out at each pass through the system, thus avoiding buildup of energy spreading in the ion population (Ref. 14).
[14]. Bussard R.W. and King K.E., “Bremmstrahlung and Synchrotron Radiation Losses in Polywell™ Systems“, EMC2 Technical Report 1291-02, December 1991.
The development of atomic power, though it could confer unimaginable blessings on mankind, is something that is dreaded by the owners of coal mines and oil wells. (Hazlitt)
What I want to do is to look up C. . . . I call him the Forgotten Man. (Sumner)
The development of atomic power, though it could confer unimaginable blessings on mankind, is something that is dreaded by the owners of coal mines and oil wells. (Hazlitt)
What I want to do is to look up C. . . . I call him the Forgotten Man. (Sumner)
A little birdy told me last week the new contract mod should be signed by the end of the month.
Thought you all might want to know.
I do find it encouraging that ONR has not only continued the project, but furthered the funding.
That said, it is not certain it will succeed as a viable device. But, we shall see. Good science.
The development of atomic power, though it could confer unimaginable blessings on mankind, is something that is dreaded by the owners of coal mines and oil wells. (Hazlitt)
What I want to do is to look up C. . . . I call him the Forgotten Man. (Sumner)