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Thursday, November 04, 2021
3:00 PM - 4:00 PM
WebEx

Postdoc Seminar

Investigations of the plasma conditions in the sheath using dust grains and nonlinear waves in weakly and strongly coupled dusty plasmas

Dr. Khandaker Sharmin Ashrafi
Baylor University

The charged dust particles can be levitated against gravity in the sheath of the plasma and can be used as probes to measure plasma parameters. An interesting phenomenon observed in dusty plasma physics is the attraction between the same polarity charged dust particles instead of repulsion. This attraction leads to the formation of different types of ordered structures, from one-dimensional to two-dimensional zigzag. It is important to know the plasma parameters such as densities, temperatures, charges on dust grain, the ion wake field formed downstream of the dust grains, as well as the flow velocities of the plasma particles to understand the mechanisms which govern this attraction. The experimental difficulties in measuring these quantities without perturbing the system require a numerical simulation. A molecular dynamics simulation is used to study the interaction between the dust grains, and the interaction between the dust grains and the ions. The model is used to investigate the variations in the electron and ion density within the sheath region. The results obtained from this study agree with the previous numerical and experimental studies. On the other hand, the nonlinearities in plasmas lead to different types of fascinating structures (solitary waves, shock waves, etc). A rigorous theoretical investigation has been made on non-linear propagation of the dust-ion-acoustic (DIA) and dust-acoustic (DA) solitary and shock waves in both weakly and strongly coupled dusty plasmas. It has been reported that these effects do not only significantly modify the basic features of the DIA and DA solitary and shock waves, but also introduce some important new features.

Host: Peter Brady