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ISR Plasma Chemistry Laboratory

ISR at the Air Force Research Laboratory

ISR plasma chemistry personnel at the lab
Physicists Shaun G. Ard (left) and Thomas M. Miller (right), and mechanical engineer John S. Williamson (center).

The Plasma Chemistry Laboratory at the Air Force Research Laboratory is supported by Boston College Institute for Scientific Research researchers. 

The laboratory contains four fast-flow chemical reactor apparatuses for studying electron and ion reaction kinetics at a range of thermal energies.  The goal is to advance the understanding of fundamental chemical interactions involving charged species.  These interactions greatly influence atmospheric plasmas, such as the ionosphere, which impact RF propagation and hence communications, as well as bond-activations employed in numerous catalytic processes such as satellite propulsion and production of energy dense rocket fuels. 

The laboratory features two selected-ion flow-tube (SIFT) apparatuses capable of studying ion-molecule reactions in detail from 100-600 K.  The temperature dependence of reaction kinetics in this regime are often sensitive to subtle mechanisms difficult to discern by other experimental methods.  Recent work integrating new ion sources has greatly enhanced the number of systems available for study in this manner.  Study of metal ion kinetics have offered insights into many catalytic processes, especially those involving fuel production, by trying to dissemble the role of spin conservation or relaxation in the course of a reaction.  Addition of a Laser Vaporization (LAVA) cluster ions source has allowed for the study of systems in the “cluster” size regime, a few to dozens of atoms, which often display properties significantly different from their bulk or atomic counterparts.  

The laboratory also includes two flowing-afterglow Langmuir-probe (FALP) apparatuses, operating from 100-1800 K.  These apparatuses enable measurement of reaction kinetics for electron-molecule, electron-ion, and ion-ion processes taking place in plasmas over an extended thermal range.  New plasma processes have been discovered in this work, e.g., electron-catalyzed ion-ion mutual neutralization.  The extended temperature range is paramount in establishing a predictive understanding of the role these processes play under conditions not currently available in a laboratory setting.

In addition, the laboratory benefits significantly from collaboration with university researchers in the U.S. and Europe.

Point of contact for this research is Shaun G. Ard.