Acoustic Waves in Dusty Plasmas - like that in Saturn's Rings - Created by Electricity

Pretty interesting article. It explains how dust within plasma that is electrically charge can created oscillating acoustic (sound) waves that can harmonically build off of each other, sometimes even producing shockwaves.

So, we have plasma and the electrically charged dust particles creating 'sound'.

The sound in Saturn's rings: RUB-Physicists explain nonlinear dust acoustic waves in dusty plasmas

Dusty plasmas can be found in many places both in space and in the laboratory. Due to their special properties, dust acoustic waves can propagate inside these plasmas like sound waves in air, and can be studied with the naked eye or with standard video cameras.

Different acoustic phenomena in dusty plasmas
Dusty plasmas are composed of electrons, positive ions, neutral atoms, and dust grains that are negatively or positively charged. Only in plasmas containing electrically charged dust grains, dust sound waves emerge - the so called dust acoustic waves. These waves are supported by the inertia of the massive charged dust particles. The restoring force - causing the particles to oscillate and the wave to propagate - comes from the pressure of the hot electrons and ions...

Dust acoustic waves with large amplitudes interact among themselves thereby generating new waves with frequencies and wavelengths different from the ones of the original dust acoustic waves...

Due to the generation of harmonics (i.e., waves with frequencies that are a multiple integer of the original frequency) and due to constructive interference between dust acoustic waves of different wavelengths, the waves develop into solitary, spiky pulses, or into shock waves. The solitary pulses arise from a balance between the harmonic generation nonlinearities and the dust acoustic wave dispersion.

These three international groups described the existence of large amplitudes dust acoustic solitary pulses and dust acoustic shocks in their low-temperature dusty plasmas. Applying the new nonlinear dust acoustic wave theory, one can infer the dust fluid viscosity from the width of the dust acoustic shock wave.

"Our results may also be important as a possible mechanism for understanding the cause of dust grain clustering and dust structuring in planets and in star forming regions," suggests Prof. Padma Kant Shukla.

[link to www.spacedaily.com]

Last Edited by Saptaparna on 10/18/2012 04:49 PM