At the most recent AIAA SciTech conference, I met a gentlemen from the Air Force Academy who teaches there and reviews research proposals for the Air Force. He gave a talk to the plasma aerodynamics group on plasma actuators and why those proposals have not been funded much recently. He also raised a point, which is the focus of this post, that plasma is not always the solution to the problem and we as a community should stop using it as a proverbial hammer to hit every problem nail.
First, a little background and explanation. As scientists and researchers, we are all trained in some specialty, whether it’s plasma physics, rocket propulsion, high speed aerodynamics, piston engines, mammalian habitats, insect DNA, etc. Of course some specialties are broader than others. So we tend to do research in our specific areas, or areas that are similar enough that we can bring a part of our experience to bear. The further the research is to our core specialty, the hard it is and less likely others will fund you or trust your results. Yes, there is some bias in science. So this specialty is what I called the “science hammer”. Like a craftsman, we have one or two types of hammers (knowledge) in our tool belt. So when we encounter a science problem, our first thought is to hit it with our hammers. Another way to say that is when you only have a hammer as your tool, then every problem is a nail to be hit.
I have been thinking on this “hammer” and the suggestion the gentlemen at SciTech gave. My hammer is plasma. I sometimes jokingly say plasma can solve all your problems, or I’m always looking for things to point a plasma at. Now plasma is a pretty energy inefficient process by its very nature. Unlike a fire, you have to continuously supply the plasma with energy and fuel to keep it going. The fire will keep burning as long as there’s fuel. Once started, the fire provides its own energy. So in many cases, especially aerospace applications where energy is limited, plasma may not be the best solution. The example the gentleman gave was plasma actuators for flow control on airplane wings. Plasma actuators can improve the flow and reduce drag on wings. But the practical question becomes is it worth it? It takes extra energy to generate and sustain the plasma, and it seems at least for plasma actuators the benefits are not worth the cost.
Now there has been considerable interesting science to come out of the last 15 years of research into plasma actuators. So all is not lost. But the funding agencies have learned a lesson if you will. They’re more cautious about plasma-based solutions since they recognize the issues with plasmas. So in my position as a principle investigator looking for funding, I am not trying to by smarter about what I apply plasma to. It has to be credible, doable, and provide a net benefit. I have also begun to look at way to use plasma not as the solution, but as a diagnostic or tool to study a phenomenon. I’ve been talking with another faculty about using plasma actuators to study flows. Hopefully the advantages of plasma can be brought to bear and without worry about its overall efficiency since it doesn’t have to fly.