2down vote According to Constraints on Dark Matter in the Solar System the following upper limits have been placed on dark matter in the solar system, based upon orbital motion of bodies in the solar system:At the radius of Earth's orbit: 1.4×10 −19 g/cm 3 At the radius of Mars's orbit: 1.4×10 −20 g/cm 3 At the radius of Saturn's orbit: 1.1×10 −20 g/cm 3 According to Local Density of Dark Matter, the density of dark matter at the Sun's location in the galaxy is 0.43GeV/cm 3 or 7.7×10 −25 g/cm 3

Quote2down vote According to Constraints on Dark Matter in the Solar System the following upper limits have been placed on dark matter in the solar system, based upon orbital motion of bodies in the solar system:At the radius of Earth's orbit: 1.4×10 −19 g/cm 3 At the radius of Mars's orbit: 1.4×10 −20 g/cm 3 At the radius of Saturn's orbit: 1.1×10 −20 g/cm 3 According to Local Density of Dark Matter, the density of dark matter at the Sun's location in the galaxy is 0.43GeV/cm 3 or 7.7×10 −25 g/cm 3 http://arxiv.org/abs/1306.5534http://arxiv.org/abs/1212.3670

....At about 1Gev/cm^3 (as seen on this seemingly optimistic paper, maybe more optimistic is possible) and .01m˛ csection and 250km/s dark flow velocity that is mflow=1e9*1.8e-36/1e-6 * 2.5e5 * 1e-2 = 4.5e-18 kg/s.With about 45*µN thrusters that yields Vej = F / mflow = 4.5e-5 / 4.5e-18 = 1e12m/s Pow = .5 mflow Vej˛ = = .5 * 4.5e-18 * 1e24 = 2.25 e6 = 2.25MW hence the 6 orders of magnitude boast (more like 5 actually with those numbers) when comparing to 20W power....

So @frobnicat used 1Gev/cm^3 which is 78680 times less than this estimate !***there is also the question about the square cross section, previously posted by @aero ***So now we are now much closer to the ballpark

QuoteSo @frobnicat used 1Gev/cm^3 which is 78680 times less than this estimate !***there is also the question about the square cross section, previously posted by @aero ***So now we are now much closer to the ballparkSo 'microwave photon created dark matter axioms' are now a leading candidate for an explanation of the physics behind the Eagleworks thruster? Looking for clarity here. The revised Dark Matter numbers appear...close(?) to what is required, anyhow.Also, monumentally stupid, maybe, but I'll ask anyhow. Even a superficial surface looksee into Dark Matter reveals...informed speculation(?)...of a whole zoo of Dark Matter particles. Maybe some of them have a bigger 'kick' than others?

So @frobnicat used 1Gev/cm^3 which is 78680 times less than this estimate question about the cross section,

QuoteSo @frobnicat used 1Gev/cm^3 which is 78680 times less than this estimate question about the cross section, I have no idea how the cross section should be estimated. I followed frobnicat's calculations but used the area of the small end of the truncated frustum thruster, which is about 0.044 m^2, and the density number above.I calculate mflow= 1.55786E-12 kg/s compared to the earlier value of 4.5e-18 kg/s.Of course I'm not even sure frobnicat was considering the truncated frustum thruster, he may be considering the Cannae device.

@frobnicatWhat is the .01m˛ csection that you refer to?Maybe you told us the definition of terms before but I didn't find them in the last 20 pages, yesterday.I wonder, because that equals 100 cm^2 or a square about 4 inches on a side and I don't recognize that dimension wrt the thruster cavity.

Took a while to find this again. http://www.gregegan.net/SCIENCE/Cavity/Cavity.html

Havn't been able to find the resonant formula I was looking for, but some interesting things in the old radar handbook. The only point of interest for axion interaction in this setup is that surface effects can change the geometric cross-section from -12db to +28db in the optical region where wavelength is small compared to size. The response of a bulk dielectric is noisy but only a few db around geometric area.Edit: no real surprise about the proper mode being important.

Quote from: Mulletron on 10/04/2014 03:35 AMTook a while to find this again. http://www.gregegan.net/SCIENCE/Cavity/Cavity.htmlThe NASA Eagleworks report shows that the resonant mode of operation is more important than the Q factor<<B. Tapered Cavity RF Evaluation and Testing, First TM211 modeFigures 18 and 19 chronicle the activities surrounding a series of five test runs at 1932.6 MHz corresponding to the first TM211 mode. In this test configuration, the VNA system indicated a quality factor of ~7320, and the difference of power forward and power reflected as reported by the power meters was indicated to be ~16.92 watts as a result of manual tuning to maximize the power difference. The (net) peak thrust observed for this tested configuration was 116 micronewtons and the (net) mean thrust over the five runs was 91.2 micronewtons.>><<C. Tapered Cavity RF Evaluation and Testing, Second TM211 modeCOMSOL® analysis indicates that there are two TM211 modes within a couple of MHz of one another for the as-built tapered thruster. The higher frequency TM211 mode has a much higher predicted quality factor (32,125), but considerably lower thrust to power performance (5 micronewtons per watt). The tapered RF system was tuned and operated at this mode for evaluation on the low thrust torsion pendulum. The measured quality factor was 18,100 with a power-forward/power-reflected difference of 16.74 watts and the average measured thrust was 50.1 micronewtons. With an input power of 16.74 watts, correcting for the quality factor, the predicted thrust was 47 micronewtons.>>Unfortunately, the NASA report only shows the frequencies, but it does not show the mode shapes. One cannot tell why a frequency of only a couple of MHz higher has a Q more than 4 times higher but a thrust force half as much as the lower frequency. It would be nice to have a picture of the mode actual mode shapes (as shown in the reference submitted by Mulletron http://www.gregegan.net/SCIENCE/Cavity/Cavity.html for a different geometry) to tell what is the difference in the mode shapes: what gets excited in the cavity that makes such a big difference.Or is the thrust force (twice higher) at the 2 MHz lower frequency not really due to the mode shape but is it due to something happening in the dielectric resonator and/or coupling with something (dark matter for example)?COMSOL® field plot for 1932.6 MHz, TM211 also shown for reference - red is electric, blue is magnetic

http://www.theory.tifr.res.in/~hbar/PDF/ti.pdf

You know, before we blame [anyone] for bringing [another] theory here...

Propeller/slow wind : power of the device is used to accelerate DM particles.