Andrew Zwicker, Emily Margolis, Everett Schlawin, and Will Gannett
Princeton Plasma Physics Laboratory
A dusty plasma is a unique physical environment where neutral atoms, electrons, ions, and charged dust particles interact to form a system relevant to the study of fields as divergent as the rings of Saturn or the creation of a computer chip. In this video, we are studying the formation process of a stable cloud of dust particles suspended in a background argon plasma. Our dust consists of micron-sized fluorescent particles that are illuminated by an ultraviolet spotlight through a window and emit visible light that is imaged by a CCD video camera. In the first five seconds of the video, we jump-start the charging process by creating a bright electrical arc that sends dust particles into the plasma. Gravity causes the dust to fall back down but it is constrained to stream along electric field lines for the next ten seconds. During this time, the larger dust particles fall back to the dust holder (out of the frame) and are no longer suspended. The remaining dust particles build up electrical charge and one can observe various instabilities hinder the particles from creating a stable cloud for the next ten seconds. Finally, thirty seconds after the start of the video, the dust particles abruptly form an organized and distinct cloud. The resulting cloud is stable and one can clearly observe the three dimensional motion of individual dust particles.