This animation shows localized electroconvection pattern excitation in a methyl-red doped MBBA nematic liquid crystal.   The sample (a 25 micron film pressed between ITO-coated glass slides), is subjected to a 590-Hz, 11.8 V (RMS) voltage across the film.  The sample is excited with a 488-nm CW laser beam (exposure time 0.6 s) focused to a diameter of about 60 microns.  Williams roles separated by about 25 microns are evident in the laser-excitation region.

The data were recorded using a CCD camera attached to an inverted microscope with a 10X objective lens.  The animation is designed to show the dynamics in real time, as observed in the lab:  the interval between frames is 0.5 s, and the total time elapsed is 20 seconds.

Data acquired April 10, 2002 in the Trinity Laser Lab.  These data are preliminary and have been web-posted only to facilitate communication; the data should not be interpreted as a complete study.  More experiments will be required to fully understand this process.

Thanks to Dr. Charles Allen for creating this animation!

-Dan Spiegel  May 13, 2002.