Help Plotting director fields

*To*: mathgroup at smc.vnet.net*Subject*: [mg120190] Help Plotting director fields*From*: Liquid Crystal <liqlearner at gmail.com>*Date*: Tue, 12 Jul 2011 06:59:25 -0400 (EDT)

Hello, I am trying to plot a director field for nematic liquid crystals. The form of the director is, in pseudo-mathematica n = {Cos[theta],Sin[theta]} Where: theta = s ArcTan[y/x] + theta_0 If you reference the following links, you will see the various disinclinations induced in the director field by choosing various s and theta_0 http://learnliquid.blogspot.com/2011/07/test.html However, using the following code I am not able to produce these images. Any suggestions? AAA = {Cos[-1/2 ArcTan[y/x] + 0/2], Sin[-1/2 ArcTan[y/x] + 0/2]} StreamPlot[AAA, {x, -1, 1}, {y, -1, 1}, StreamPoints -> 12, AspectRatio -> 1, StreamScale -> None] Thank you, LL

**Follow-Ups**:**Re: Help Plotting director fields***From:*Heike Gramberg <heike.gramberg@gmail.com>