Hi Rand, Thanks for your reply. In fact, I ask this question since I am not sure whether the result 'ex.XXXXXX.XX.h5' is in SI unit since I have to use the result to calculate the SAR value. I guess you are doing the similar work as me, do you?
>Actually I noticed your email and I just want to verify if it is state anywhere in Meep That e->field Is converted to the formula stated in your email? And do you mean that they multiply the >answer of the e-field with sqrt(epsilon-0/mu-0)? No, I did not mean that it is stated that e-field is converted to the formula. Here I describe my question again specifically. The first step I want to do is described here: http://www.mail-archive.com/[email protected]/msg00386.html, since we need to know the E-field exposure (W/m2) before we start the FDTD simulation. When I use the electric-energy-in-box function by C++. I found the value became smaller and smaller from 2000 to 0.005. And this electric-energy value came to stable status only after 10000 time steps. According to Steven's answer, I guess that I need to set the amplitude of E-field to sqrt(10/0.005) if I need the E-field exposure to be 10W/m2. But I am still curious about the result of electric-energy-in-box. How can it decrease from about 2000 to 0.005. Is there any conceptions that I misunderstand? Best Regards! 2009/1/16 rand mouradi <[email protected]> > Hello Yan > I think you asked about my university and I was too busy during the last > period. I'm from Cleveland State University. > Actually I noticed your email and I just want to varify if it is state > anywhere in Meep That e-field Is converted to the formula stated in your > email? And do you mean that they multiply the answer of the e-field with > sqrt(epsilon-0/mu-0)? > Thanks > > ------------------------------ > *From:* Yan Liu <[email protected]> > *To:* [email protected] > *Sent:* Tuesday, January 13, 2009 1:28:19 AM > *Subject:* [Meep-discuss] : To get the value of E-field by SI > > Hello! everyone, > First, I am not very sure of the specific way to generate E-field in MEEP. > In FDTD method, the E-field is converted to > sqrt(epsilon_0/mu_0) where epsilon_0 = 8.85e-12, mu_0 = 1.2566e-6. I > wonder how to transfer the result of E-field to the SI value (V/m). > > Second, in this link > http://www.mail-archive.com/[email protected]/msg00386.html > Steven said that we need to calculate the 'amplitude' by the following > step: > > >Suppose you want to input 5W of power into a waveguide (or whatever). What > you should do is to put >a source with some amplitude "A" and measure the > power P that you get in >your waveguide (using one of Meep's flux functions). > Then to make the power >5, you should scale A by sqrt(5/P). > > I wonder how I can deal with it under C++ interface? > > Best Regards! > -- > -- Thanks! Yan Liu Department of Biomedical Engineering, Huazhong University of Science and Technology Phone: (86)-130-7129-6471 Personal Website: sites.google.com/site/yanliurf
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