This research will push the current boundaries of plasma physics to create and control the smallest plasma discharges. The goal is to find out how to make and to use nanoscale plasma discharges as tools for the highly localized diagnostics and modification of matter. Furthermore this proposed work will increase the exposure of the general public and future graduate student to the exciting and interdisciplinary field of plasma engineering.
This proposed research experimentally investigates micro- and nano- scale discharges in liquids. By using nanosecond duration voltage pulses, nanoscale electrodes, and a high density medium such as a liquid, plasma discharges as small as 10s-100s of nanometers in size can be created. Such systems are very complicated with various effects of the plasma generation including: electrophoresis, shock waves, radical species generation, non-equilibrium conditions, light emission, high pressures and high temperatures. The temporal evolution of the thermodynamic state in the small discharges will be measured and manipulated by voltage pulse control to emphasize desired effects for a particular application. Diagnostics will include sub-ns temporal resolution microscopic visualization, optical emission spectroscopy (OES), Schlieren imaging and hydrophones. The experimental results will be correlated with analytical and low-order models comparing the system to existing theories on underwater electrical and laser induced breakdown. These results will be tied into developing course material, and disseminated to students, the general public, and research peers.
Intellectual Merit: The hypothesis of this research is that nanoscale plasma discharges can be created to accentuate various physical, chemical, radiative, or thermal effects by controlling the electrode size, and voltage application. This study of miniscule discharges in high density fluids pushes the limits of current low temperature plasma physics to smaller sizes and higher electron densities. Diagnostic techniques will also be developed in this new regime. Proof of concept tests for some potentially transformative applications will also be explored such as: the chemical analysis of attoliter volumes of liquids; intracellular surgery and diagnostics; maskless nanopatterning; bottom-up nanofabrication; and hydrodynamic flow control. Future potential applications of these unique small size, high energy density, and luminous systems are: nanoscale thermonuclear devices; sub-wavelength visible and UV light sources for near field optical techniques; electro-optical interconnects and, yet unexplored quantum confinement effects in nanoscale plasmas.
Broader Impact: The study of such plasma liquid interaction and their applications is important as it is a new regime of plasma physics ripe for new technologies and discoveries. Similarly the nanoscale manipulation of materials and processes is also important. The proposed research focuses on very fundamental aspects, mechanisms and applications with nanoscale plasmas. As a novel system it also has potential for new commercial applications. To enhance educational impacts this proposal will: 1) train and exposure undergraduate, master and doctoral students in the cross disciplinary field of plasma engineering, 2) develop a new undergraduate course on Plasma Engineering including laboratory demonstrations, 3) develop a workshop and seminars on nanoscale plasmas and plasmas in liquids for several international meetings, 4) focus on increasing graduate school participation of domestic students including the underrepresented, and 5) create You-Tube and Wikipedia content to excite and inform the general public about plasmas.
