Study spots fluffy ice grains that float and swirl inside cold plasma

Researchers at Caltech have recreated the extreme conditions found in deep space—combining icy dust, electrified gas, and freezing temperatures—to study the behavior of ice grains within cold plasma. Inside their cryogenic plasma chamber, they observed tiny ice grains spontaneously forming delicate, snowflake-like fractal structures. These grains became negatively charged as electrons accumulated on their fluffy surfaces, resulting in a high charge-to-mass ratio that caused electrical forces to dominate over gravity. Consequently, the grains did not settle but instead floated, spun, and swirled in complex vortices within the plasma, exhibiting unpredictable motion even as they grew much larger and fluffier. The negatively charged grains repelled each other and drifted through the neutral gas like feathers in the wind, influenced by inward-pointing electric fields that trapped them inside the plasma. This behavior has significant implications for understanding dusty plasma environments in astrophysics, such as Saturn’s rings, star-forming molecular clouds, and protoplanetary disks, where charged