Renowned for his expertise in plasma physics and aerospace engineering, Dr. Sergey Macheret has carved out a prestigious career across both academic and industrial landscapes.
Originally from Kiev, Ukraine, he acquired his M.S. in Physics from the Moscow Institute of Physics and Technology and later obtained his Ph.D. in Plasma Physics and Plasma Chemistry from the Kurchatov Institute of Atomic Energy. Macheret’s professional journey includes positions at the Ohio State University, Princeton University, and Purdue University, as well as significant contributions to cutting-edge aerospace projects during his time at Lockheed Martin’s Skunk Works. In 2014-2024, he worked at Purdue University as a Professor of Aeronautics and Astronautics, expanding his role in 2022-2024 to include a professorship in Electrical and Computer Engineering. Dr. Macheret further extended his influence into entrepreneurial ventures by founding US Plasma Engineering LLC in 2023, which specializes in pioneering plasma technologies. An elected Fellow of the American Institute of Aeronautics and Astronautics, he has received accolades such as the 2022 AIAA Plasmadynamics and Lasers Award, highlighting his trailblazing contributions to the field. His extensive publication record, featuring over 170 papers, several books and book chapters, and numerous patents, further attests to his profound impact on science and technology.
What inspired you to pursue a career in plasma science?
During my early education, I got interested in fundamental microscopic interactions among atoms, molecules, electrons, and ions, and I was fascinated by the complex macroscopic behaviors of gases and plasmas stemming from those fundamental microscopic interactions. In other words, I was excited about the beautiful science of plasmas and molecular processes. Later on, I learned that plasmas also play a critical role in both natural phenomena and practical technologies, which got me even more excited, and I decided to devote my career to studies of fundamental processes in plasmas and to development of novel plasma-based technologies.
How has the transition from academia to industry and back influenced your approach to research?
The transition has been immensely enriching. The great thing about academia is that you are free to explore any idea (well, provided that you can get some funding for that). However, the “publish or perish” environment results in the majority of publications representing just incremental advances rather than real breakthroughs.
At Skunk Works, I was fortunate to work in a unique environment where incremental advances are viewed as meaningless, and you have to come up with ideas that are real game-changers while also being practical. In addition, in the Skunk Works culture, research and development is done at a truly breakneck speed, and more is done in a few weeks or months than would be done in academia in years.
Returning to academia with this experience and perspective definitely changed the way I approached research and allowed me to guide students accordingly.
Can you discuss a project that significantly impacted your career?
Two projects that started in the late 1990s and continued into the early 2000s, when I worked at Princeton University, have profoundly affected my career.
One project was prompted by the claims made in the literature that weakly ionized plasmas can weaken or even eliminate shock waves and that a combination of plasmas and magnetic field can dramatically increase performance of the so-called scramjet engines for hypersonic airbreathing vehicles. In that project, those claims were debunked, but then a profound insight into the interaction of plasmas with supersonic and hypersonic flows was developed, and new ways of plasma control of such flows were proposed and studied.
The other project was motivated by the extremely high power required to sustain plasma in air, and the goal was to reduce the power budget by orders of magnitude. That project resulted in novel ways of generation and control of plasmas, including the use of electron beams and repetitive high-voltage nanosecond pulses.
Both projects not only changed my career but also affected the entire field of aerospace application of plasmas.
What challenges do you face in your current research?
One major challenge is the integration of emerging plasma technologies with existing systems, both in aerospace and non-aerospace applications. The existing systems have stringent requirements and have already been optimized with established technologies that are not easily displaced or augmented with new methods like plasma-based solutions. Overcoming these challenges requires interdisciplinary collaboration and persistent innovation.
What future developments in plasma technology and its applications do you find most promising?
Since plasmas are powered by electricity and can efficiently stimulate chemical reactions, plasma technology can potentially become a critical element in the global “green transition” for the entire chemical industry so that the primary energy source would change from burning hydrocarbons to the use of renewable electrical energy.
Another class of applications is made possible because plasmas, on one hand, efficiently interact with electromagnetic signals, and on the other hand, can have their properties quickly changed. This can potentially enable plasma-based systems for electromagnetic interactions and control, such as tunable and reconfigurable radio-frequency antennas, filters, limiters, etc.
What advice would you give to students interested in pursuing a career in plasma science and technology?
I would advise students to cultivate a strong foundation in both physics and applied mathematics, as these are crucial for understanding and innovating in plasma science and engineering. The deeper and wider your fundamental knowledge the easier you will adapt to rapidly changing technology and new tasks. Moreover, the students should develop a deep understanding of the underlying physical phenomena and the ability to perform rough, order-of-magnitude, estimates; this cannot be ‘outsourced’ to computers by feeding them long rigorous equations. Equally important is gaining hands-on experience through internships and research projects in diverse settings, including both academia and industry, to understand the practical applications of their knowledge.
Reflecting on your career, what do you consider your greatest achievement?
I discussed two of my principal achievements, i.e. my contributions to plasma aerodynamics and to highly efficient plasma generation and control, in my answer to the question about projects which significantly impacted my career. Those achievements brought me honors and awards. In addition, I am also proud of my work on the theory of chemical reactions, particularly dissociation of molecules and bimolecular exchange reactions, in thermal nonequilibrium where the vibrational temperature of molecules is much higher (as occurs in electric discharge plasmas) or much lower (which occurs in hypersonic shock layers) than the temperature of translational motion.
