OBSERVATION OF DUST SHEDDING FROM MATERIAL BODIES IN A PLASMA

Exposure to a space plasma can cause a dusty body, such as a spacecraft or a boulder in Saturn's rings, to release dust into its environment. This is demonstrated in a laboratory experiment with an aluminum sphere covered with micrometer-sized dust grains. The sphere was rotating and electrically floating like an object in space. Laser light scattering was used to detect dust falling from the body. When a low-temperature nitrogen plasma was turned on, rapid dust shedding was observed, and when it was turned off, the shedding stopped. The rate of shedding increases with plasma density. The dust is not all released the instant the plasma is turned on but rather takes place over an extended period of time, with individual grains jumping off at random intervals with a certain probability per unit time.