tag:blogger.com,1999:blog-4637778157419388168.post9188186689521301432..comments2017-04-26T06:00:49.162-07:00Comments on Physics from the edge: The Data's the ThingMike McCullochhttp://www.blogger.com/profile/00985573443686082382noreply@blogger.comBlogger6125tag:blogger.com,1999:blog-4637778157419388168.post-17506281093816975002017-02-24T05:20:41.287-08:002017-02-24T05:20:41.287-08:00Hi Mike,
I've re-read your paper. I can gener...Hi Mike,<br /><br />I've re-read your paper. I can generally follow the substitutions and equation wrangling, with some queries:<br /><br />- I'm not sure how we get from equation (5) to (6).<br /><br />- I'm not sure what's going on with equations (8) and (9); I can see where they come from, but don't really understand the justification. I know next to nothing about electromagnetic resonance; maybe I'm put off by the idea of having 6 orthogonal directions in 3-dimensional space :)<br /><br />- I don't follow the justification of the substitution of (8) and (9) into (7) to give (10); unless I'm missing something, this isn't a straight substitution, Ws bar and Wb bar aren't the same as Ws and Wb, so I'm not sure how you can substitute one for the other.<br /><br />- Similarly, I'm not quite sure how we can just throw Q in to get (14) (I understand the photons will resonate for a time, of course).<br /><br />Anyway, my uncertainties may not matter: if the model is as simple as chopping the cavity into cells and applying known equations and iterating over time, that's easily done. A complete quantum simulation, however, is probably beyond my spare time capabilities :)<br /><br />Jamie<br />Jamiehttp://www.blogger.com/profile/09542209420094720858noreply@blogger.comtag:blogger.com,1999:blog-4637778157419388168.post-44663691946696949702017-02-23T11:04:15.704-08:002017-02-23T11:04:15.704-08:00Jamie: Thanks for the offer of help. It's diff...Jamie: Thanks for the offer of help. It's difficult :) What needs to be done is to develop some code to determine the distribution of accelerations of photons in the emdrive cavity. Then the Unruh waves they see and how those will be damped in the emdrive. Have you read my paper?: https://arxiv.org/abs/1604.03449Mike McCullochhttp://www.blogger.com/profile/00985573443686082382noreply@blogger.comtag:blogger.com,1999:blog-4637778157419388168.post-41957695429599410352017-02-22T17:59:51.915-08:002017-02-22T17:59:51.915-08:00"A small 5 MW reactor with 5% efficiency &quo..."A small 5 MW reactor with 5% efficiency "<br /><br />Meaning, a small 5 MW rated electrical output nuclear reactor coupled with a RF cavity drive with 5% output efficiency...joesixpackhttp://www.blogger.com/profile/08912279232742819732noreply@blogger.comtag:blogger.com,1999:blog-4637778157419388168.post-55301636459705401712017-02-22T17:22:17.103-08:002017-02-22T17:22:17.103-08:00Sir,
I have a sensible question and a rather sill...Sir,<br /><br />I have a sensible question and a rather silly one followed by one I saw from a discussion on the EM drive wiki.<br /><br />What kind of efficiency can an RF cavity thruster achieve?<br /><br />Several developments have taken place in the last few years:<br /><br />Shawyer's 2nd generation EM drive paper, where he even describes a prototype spacecraft.<br />The creation of metallic hydrogen, which is purported to be a room temperature superconductor.<br />Optimisation techniques have been applied to the dimensions of the cavities.<br />The optimal magnetic fields have been researched for Hall thrusters (could this improve Q for RF cavity thrusters?).<br /><br />My view is that if the EM drive gets 5% or more input/thrust efficiency, spaceflight becomes a new normal. From what I can find, the best RF cavity thrusters have an efficiency of less than one tenth of one per cent. A small 5 MW reactor with 5% efficiency would produce enough thrust for viable spaceflight and orbital launch, as well as painless "flight" and fantastic flight properties.<br /><br />Now for the silly question:<br /><br />Would it be possible to build a multi-stage EM drive where different semi-reflective meta materials of different cavity shapes are held within a larger cone. So basically it might consist of a large cone with 20-30 small EM drives/Cannae drives to maximise the waveguide/interference producing the thrust?<br /><br />Finally would it be possible to create a "cone-less" drive where diodes(?) create their own "virtual cone" by changing what is switched on and not at differing frequencies?<br /><br />There is clearly a lot to learn. We're not even at the "Model-T" stage of this technology yet, despite going back to the 1950s, for the ideas that inspired Shawyer.joesixpackhttp://www.blogger.com/profile/08912279232742819732noreply@blogger.comtag:blogger.com,1999:blog-4637778157419388168.post-56574062044743823922017-02-22T06:18:03.302-08:002017-02-22T06:18:03.302-08:00Hi Mike,
I've been thinking the same thing. ...Hi Mike,<br /><br />I've been thinking the same thing. I've found an open source microwave simulator here: http://www.petr-lorenz.com/emgine/ <br /><br />I've had the idea that once we are able to accurately simulate the microwave distribution inside an emdrive cone, since it's open source we could also apply QI principles to the simulation and directly calculate expected thrust.<br /><br />Once we have that running accurately, a genetic algorithm could be applied. Repeat simulations until we generate something optimal. One of the (incorrect) criticisms I keep hearing about your theory (I'm looking at you Forbes) is that the emdrive's signal is less than the noise. If we could generate an optimal shape that could potentially buy us an order of magnitude and make the thing jump off the desk, I think that would be a lot harder to brush off.<br /><br />Besides, I want my flying car. :)<br /><br />RichRichDhttp://www.blogger.com/profile/06862524025762952800noreply@blogger.comtag:blogger.com,1999:blog-4637778157419388168.post-8593396083023519382017-02-22T05:02:07.745-08:002017-02-22T05:02:07.745-08:00Hi Mike,
What's required to build the compute...Hi Mike,<br /><br />What's required to build the computer model? I have a good undergraduate maths degree, and 18 years professional experience building software (including developing several physical rigid and soft body simulation models for real-time use and implementing various numerical integrators), so I might be able to help if the maths isn't too demanding.<br /><br />JamieJamiehttp://www.blogger.com/profile/09542209420094720858noreply@blogger.com