Velocity shear instability in dusty plasmas

The velocity shear instability in a magnetized, three-component dusty plasma is investigated for both positively and negatively charged dust particles. The critical shear as a function of the relative charge of dust grains is of the same form for both positively and negatively charged dust grains. The instability excitation is easier in colder proton's environment for positively charged dust, and so also in colder electron's environment for negatively charged dust. For a certain how pattern, the instability excites in different directions for different signs of the charged dust grains. This conclusion may be helpful in interpreting the helical structures and the phenomenon of streamer splitting in cometary tails.