From: "Terrell W. Fritz"
Date: Thu, 07 Mar 2002 18:50:27 -0700
Subject: Re: [TSSP] Progress on capacitance program
Hi Paul, WOW!! neat! :-)) I once tried this with E-Tesla6 but gave it up for being too messy for me to handle. If your program can put out an X vs. Y grid file that could be plotted as a contour plot, it would be neat to see how the dielectrics affect the fields. Cheers, Terry At 07:34 PM 3/7/2002 +0000, you wrote: >Hi All, > >At last I can report a bit of progress on the capacitance program. > >This is the program which computes the physical cap of the resonator - >the first step in modeling the system. > >The program tcap's main defect is that it doesn't take account of >varying material dielectrics - it just assumes that all the conductors >are immersed in a uniform dielectric. As a result, we tend to under- >estimate the capacitance of the system, most notably on small coils >and small h/d coils, where the coil former thickness is significant. >This is unfortunate, as in order to demonstrate some of the more >interesting effects of capacitance, we need to be able to explore the >small coil and small h/d domains more accurately. Thus the goal is to >alter tcap to take proper account of dielectric materials, eg coil >formers, bases and pedestals, insulating walls, coil supports, etc. > >The whole procedure is described beautifully in a paper > > http://faculty.smu.edu/tausch/Papers/mtt1.ps.gz > >and basically I just need to add in the stuff from equ (5). In order >to make room in the program, I've speeded up the whole thing quite >a bit, and at the same time made it more accurate! For example, a >test case involves calculating the self capacitance of a unit sphere, >which is known to be 111.2650pF. Tcap takes 9 seconds to deliver an >answer of 111.2672pF. The accuracy falls to around 1% on unfavourable >geometries, but the program will now compute the self and mutual >capacitances for any shape of object that has cylindrical symmetry. >In other words, any oddball shape that can be described to acmi can >be also be fed into tcap. The calculation of the self-C of isolated >objects like toroids, cones, discs, whatever, is now the most >accurate that we've had, and also the quickest, thanks to a few >computational tricks. It takes around 6 minutes to compute the >capacitance matrix for the whole resonator. Total Cdc of objects >like secondaries and toroids takes just a few seconds to 1%. > >The upshot is that there is now plenty of spare capacity in the >program to allow the ECF code to go in. I just need to find the time >and determination to do it. > >There are quite a few other tricks that we can draw on, some of which >are described in > > http://faculty.smu.edu/tausch/Papers/advCM.ps.gz > >These two papers have been a considerable source of inspiration >lately. I'm very grateful to their authors for choosing to use the >same kind of integral operators that I've found useful for describing >the resonator in pn1401. >-- >Paul Nicholson, >--
Maintainer Paul Nicholson, paul@abelian.demon.co.uk.