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by TheRadicalModerate
Sat Oct 28, 2017 10:22 pm
Forum: News
Topic: SpaceX News
Replies: 1936
Views: 186392

Re: SpaceX News

dont forget the 10 tons vernier trusters Where are you getting that number from? The only thing I heard about BFR thrusters was from Musk's recent reddit AMA: The control thrusters will be closer in design to the Raptor main chamber than SuperDraco and will be pressure-fed to enable lowest possible...
by TheRadicalModerate
Fri Oct 27, 2017 6:18 pm
Forum: News
Topic: SpaceX News
Replies: 1936
Views: 186392

Re: SpaceX News

One problem with a lower G launch is increased gravity losses, increasing the delta-V the engines need to produce. Eh, start at 1.3, ramp over 10 seconds to 2.5. Fuel is cheap. Sure, but that's not the question. The question is does BFR have the fuel capacity to do so. Per the analysis I did up-thr...
by TheRadicalModerate
Fri Oct 27, 2017 6:16 pm
Forum: News
Topic: SpaceX News
Replies: 1936
Views: 186392

Re: SpaceX News

But remember it has to fill 4 different jobs with the engine selection. Sub-orbital point to point, orbital point to point, LEO at least to space station range with 173 ton payload and MARS. At least according to grand plan using only two different types of engine. Note that, during the recent redd...
by TheRadicalModerate
Fri Oct 27, 2017 2:59 am
Forum: News
Topic: SpaceX News
Replies: 1936
Views: 186392

Re: SpaceX News

So why don't we do the back of the napkin, as I have been suggesting. Let's do it with what we know, and the goal of minimizing g stress on pax. Since nothing about rockets makes sense until you run the delta-v numbers, here's the back of a slightly bigger napkin: The BFR breaks down as follows: BF...
by TheRadicalModerate
Sun Jul 30, 2017 8:16 pm
Forum: News
Topic: Placing humans at center of computer optimization yields hot plasmas
Replies: 6
Views: 682

Placing humans at center of computer optimization yields hot plasmas

Tri-Alpha is using kind of an interesting combination of genetic algorithm, physical test setup, and human as an objective function to do optimization on the plasma stability in the colliding FRCs.

At Ars Technica here.
by TheRadicalModerate
Sat Nov 12, 2016 10:01 pm
Forum: News
Topic: Sandia to Use Tritium In Z Machine
Replies: 0
Views: 4509

Sandia to Use Tritium In Z Machine

https://share.sandia.gov/news/resources/news_releases/tritium_fusion/#.WCePydwkgt9 Not clear whether this will be a MagLIF experiment or not. Notice the reference to "pre-warmed plasma", which makes me think it's at least being zapped with a laser, so why wouldn't you add the axial B-field...
by TheRadicalModerate
Wed Apr 20, 2016 6:45 pm
Forum: News
Topic: EM Drive
Replies: 642
Views: 121445

Re: EM Drive

The Curious Link Between the Fly-By Anomaly and the “Impossible” EmDrive Thruster.

The assertion here is that it's quantized Unruh radiation.
by TheRadicalModerate
Sun Jan 24, 2016 5:51 am
Forum: News
Topic: Some Tokamak Turbulence Progress
Replies: 2
Views: 814

Some Tokamak Turbulence Progress

New finding may explain heat loss in fusion reactors. The expectation by physicists for more than a decade had been that turbulence associated with ions (atoms with an electric charge) was so much larger than turbulence caused by electrons — nearly two orders of magnitude smaller — that the latter ...
by TheRadicalModerate
Fri Jan 01, 2016 6:50 pm
Forum: News
Topic: Laser fusion again...
Replies: 7
Views: 1599

Re: Laser fusion again...

This talk of a very short coherent light pulse driving implosion has me pondering monopulse millimetre wave driven implosion, the longer wavelengths being far easier to generate efficiently. Remember that the way you get these ultra-short pulses is by compressing a relatively long pulse (or pulses)...
by TheRadicalModerate
Fri Jan 01, 2016 7:03 am
Forum: News
Topic: Laser fusion again...
Replies: 7
Views: 1599

Re: Laser fusion again...

hanelyp wrote:
as the pulse width starts to approach the wavelength ...

... Electric fields associated with the pulse become an important element in driving the implosion.


Exactly. Ponderomotive effects start to swamp thermal effects.
by TheRadicalModerate
Wed Dec 30, 2015 11:20 pm
Forum: News
Topic: Laser fusion again...
Replies: 7
Views: 1599

Re: Laser fusion again...

This sounds a little bit like the paper I referenced here. Lasers might start to get interesting as the pulse width starts to approach the wavelength.
by TheRadicalModerate
Thu Nov 26, 2015 8:00 pm
Forum: News
Topic: p-B11 Fast Ignition Scheme Using PW, ps-scale Laser Pulses
Replies: 10
Views: 8914

Re: p-B11 Fast Ignition Scheme Using PW, ps-scale Laser Pulses

This ain't NIF. This is not thermal compression of the pellet, but electromagnetic compression induced using two picosecond lasers; and the claimed gain is enormous. A gain of several hundred. So a Q of several tens in hardware. Close to the claimed gain for Winterberg's 2003 design, which also use...
by TheRadicalModerate
Sat Nov 21, 2015 10:26 am
Forum: News
Topic: p-B11 Fast Ignition Scheme Using PW, ps-scale Laser Pulses
Replies: 10
Views: 8914

Re: p-B11 Fast Ignition Scheme Using PW, ps-scale Laser Pulses

This ain't NIF. A coil is used to generate the cylindrical kiloTesla field via laser 1 on figure 2 and that coil looks expendable. So each shot from what I am gathering will involve a PB11 pellet and sacrificial coil. I suspect that the coil/copper sleeve is sacrificial, but note that it's picking ...
by TheRadicalModerate
Sat Nov 21, 2015 2:30 am
Forum: News
Topic: p-B11 Fast Ignition Scheme Using PW, ps-scale Laser Pulses
Replies: 10
Views: 8914

p-B11 Fast Ignition Scheme Using PW, ps-scale Laser Pulses

Here's a group that's claiming they can get ponderomotive acceleration of blocks of plasma in a magnetized target: http://docs.google.com/viewer?url=http%3A%2F%2Farxiv.org%2Fpdf%2F1510.02465.pdf Seems like a long shot to me, but it's kinda interesting. I think this is old (70's and 80's) theoretical...
by TheRadicalModerate
Fri Aug 21, 2015 5:02 pm
Forum: News
Topic: Spherical Tokamaks
Replies: 10
Views: 2314

Re: Spherical Tokamaks

Dr. Bussard liked spheromaks. We had a visit from Paul Koloc one day, where they discussed their ideas for fusion. Paul was using spheromaks as a model for ball lightning at that point. Essentially, a spheromak's shape is so natural for the magnetic fields that it can exist without the physical mac...

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