MAE 298 Seminar:Toroidal plasmoid generation via extreme hydrodynamic shear

McDonnell Douglas Engineering Auditorium (MDEA)
Morteza (Mory) Gharib, Ph.D.

Hans W. Liepmann Professor of Aeronautics and Medical Engineering 
Director, Graduate Aerospace Laboratories 
Director, Center for Autonomous Systems and Tech.
Booth-Kresa Leadership Chair, Center for Autonomous Systems and Tech. 
California Institute of Technology

Abstract: Saint Elmo’s fire and lightning are known forms of naturally occurring atmospheric pressure plasmas. As a technology, non-thermal plasmas are induced by artificially created electromagnetic or electrostatic fields. Here we report the observation of a unique case of a naturally formed plasma created in the air at room temperature without external electromagnetic action by impinging a high-speed microjet of deionized water on a solid dielectric surface. We demonstrate that triboelectrification from extreme and focused hydrodynamic shear is the driving mechanism for generating energetic free electrons. Air ionization results in a plasma that, unlike the general family, is topologically well-defined in the form of a coherent toroidal structure. Possibly confined through its self-induced electromagnetic field, this plasmoid is shown to emit strong luminescence and discrete frequency radio waves. 

Bio: Professor Morteza (Mory) Gharib received his Ph.D. in aeronautics (fluid mechanics) from the California Institute of Technology in 1983. Since graduating from Caltech, he has been a faculty member in the Department of Applied Mechanics and Engineering Sciences at the University of California, San Diego (1985-1993) and then a professor of aeronautics at the Graduate Aeronautical Labs at the California Institute of Technology (1993-2001). Gharib is currently a Hans W. Liepmann professor of aeronautics and technology, the chair/director of the Graduate Aerospace Department/Laboratories, and the Booth-Kresa Leadership chair for the Center for Autonomous Systems and Technologies. His main research interests cover a range of topics in fluid dynamics and aeronautics. These include vortex dynamics, active and passive flow control, autonomous flight, underwater systems and robotics, as well as advanced flow-imaging diagnostics. His biomechanics and medical engineering research activities can be categorized into two main areas: the fluid dynamics of physiological machines (such as the human circulatory system and aquatic breathing/ propulsion) and the development of medical devices (such as heart valves, cardiovascular health monitoring devices and drug delivery systems.