They then observed that the grains<\/a> quickly became negatively charged as fast-moving electrons accumulated on their fluffy, fractal structures. As a result, they didn\u2019t settle to the bottom of the chamber the way solid particles normally do.<\/p>\n \u201cIt turns out that the grains\u2019 fluffiness has important consequences,\u201d Bellan stated. \u201cThey are so fluffy that their charge-to-mass ratio is very high, so the electrical forces are much more important than gravitational forces.\u201d<\/p>\n Instead, the grains dispersed throughout the plasma and began bobbing up and down, spinning and whirling in vortices, a phenomenon the Nicolov described as \u201ccomplicated\u201d and difficult to predict.<\/p>\n This behavior continued even for ice grains<\/a> that expanded to sizes hundreds of times larger than the solid plastic spheres previously used. The larger the grains became, the fluffier their structure turned.<\/p>\n \u201cThe microscopic fluffy structure of the grains impacts the motion of the whole cloud of grains and the plasma,\u201d Nicolov noted. The grains were trapped within the plasma by an inward-pointing electric field. <\/p>\n Unexpected dynamics<\/p>\n Because they\u2019re all negatively charged, the grains repelled one another, spreading out without colliding. According to the team, their fluffy structure made them drift through the neutral gas like feathers in the wind.<\/p>\n They believe the findings could help them better understand dusty environments in astrophysics, where charged ice grains interact. These include regions such as Saturn\u2019s rings<\/a>, star-forming molecular clouds, and protoplanetary disks.<\/p>\n As grains have large surface areas and high charge-to-mass ratios, they can act as intermediaries, transferring momentum from electric fields to the neutral gas around them.<\/p>\n \u201cYou could make a wind where the electric field pushes the dust grains, which then push the neutral gas,\u201d Bellan stated. He added that these tiny fluffy grains might even be responsible for gas and dust streaming across the galaxy.<\/p>\n Nicolov said the findings may also aid semiconductor manufacturing, where dust formed inside industrial plasmas can settle onto tiny chip features and ruin them. <\/p>\n Understanding how they grow and move could help improve their control and removal. \u201cIf you want to control the grains, you have to take into account this fractal nature,\u201d Nicolov concluded in a press release<\/a>.<\/p>\n![\"\"](\"https:\/\/www.europesays.com\/ie\/wp-content\/uploads\/2025\/12\/A2_62ae51.jpg\" "\\"Fluffy")
The instrumental setup used to study ice grains in a cryogenically cooled plasma system in Bellan\u2019s lab at Caltech.
Credit: Bellan Plasma Group \/ Caltech<\/a><\/p>\n![\"\"](\"https:\/\/www.europesays.com\/ie\/wp-content\/uploads\/2025\/12\/A5-1.png\" "\\"Fluffy")
The cloud of ice grains exhibits complex motion between the electrodes that maintain the plasma in the experimental setup.
Credit: Bellan Plasma Group \/ Caltech<\/a><\/p>\n