* Video sent by Dan Petersen sparkdoctor@gmail.com

* Email sent by Dan Petersen with the attached video:

“During my time in Hallet's lab I was working on a basic version of an experiment to study e-induced aggregation. I used a chest freezer with temps of around -20 to -25 C, filling it with a droplet cloud generated from an ultrasonic nebulizer and nucleating crystal growth with dry ice. I had separated the freezer into a 'growth' compartment and an observational compartment with two parallel plate electrodes through which the ice particles could fall. THey fell onto a glass slide, and I recorded what fell on the slide with a bottom-mounted video camera. I just dug out my old hard drive, and found what you may be looking for. See these two very short mpeg-2 clips that show chain aggregate 'trees' falling over. If you want more, I can send the full video clips which show the actual e-induced attachment behavior. It looks like a double-headed feedback exists whereby aggregates fall faster through the surrounding ice particle cloud and, due to polarization, further enhance the electric field at their extremities. Thus, they become efficient 'sweepers' of ice and can get pretty large. Probably the size is limited by environmental or self-induced turbulence. Screen width is approximately 1-2 mm across”

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Video: