Jiří Fujera is a doctoral student in the Physics program at the Faculty of Science, Masaryk University. Under the supervision of Associate Professor Tomáš Homola, he specializes in low-temperature plasma physics. He is a member of the Plasma Nanotechnology and Bioapplications group at the Institute of Physics and Plasma Technology. He also works at the Institute of Plasma Physics of the Czech Academy of Sciences (IPP CAS) in Prague, where, under the guidance of Dr. Milan Šimek, he focuses on optical diagnostics of plasma discharges and their applications, such as in agriculture or the analysis of auroral radiation spectra.
In July and August 2025, he will undertake an international internship at the prestigious Massachusetts Institute of Technology (MIT), where he will be involved in electro-optical diagnostics of plasma in a methane-air mixture for plasma-assisted combustion purposes. His research connects experimental data with theoretical models and opens new possibilities for international cooperation in the field of plasma technologies.
Could you briefly introduce yourself and explain what you do in your doctoral studies and research?
My original field of study was physics of thermonuclear fusion, but I almost immediately shifted my research focus to low-temperature plasma. In my bachelor's thesis, I worked on ozone generation, while my master's thesis focused on plasma interactions with water interfaces. Both theses were supervised by Associate Professor Homola.
Currently, during my doctoral studies, I primarily concentrate on optical diagnostics of discharges occurring near the water interface. My goal is to characterize the plasma dynamics in detail, identify the generated reactive species, and analyze their interactions with the liquid phase. These findings contribute to a deeper understanding of processes at the plasma–water interface, which have significant application potential in water treatment and environmental technologies, such as nitrogen fixation from air into the water phase.
At Masaryk University, I act as support for interdisciplinary research activities. I am especially involved in conducting and analyzing optical diagnostics for experiments carried out by other teams and in preparing technical designs and construction drawings of experimental reactors. This work requires both detailed knowledge of experimental methods and the ability to link theoretical requirements with practical apparatus implementation.
However, most of my time is spent working at the IPP, where, alongside optical diagnostics, we also produce nitrogen-enriched water through plasma discharges and treat seeds (currently barley) with plasma. Recently, we have also established cooperation with a Japanese research group focused on auroral radiation spectrum analysis and with an Italian team specializing in laser plasma diagnostics.
How did you obtain the internship at MIT?
It is one of the doctoral students’ obligations at Masaryk University to complete an international research internship. After considering several options, I chose the prestigious Massachusetts Institute of Technology (MIT), regarded as one of the best, if not the best, universities in the world. There, I joined the group led by Carmen Guerra-Garcia, which focuses on linking plasma physics, combustion, and aerodynamics research. Dr. Milan Šimek from the IPP CAS in Prague, who has a long-standing excellent professional relationship with Professor Guerra-Garcia, helped facilitate this collaboration.
How did you handle funding and visa matters?
The internship is financed through the FreeMover program and a Masaryk University scholarship. To obtain a visa, I had to prove monthly financial funds of approximately 4,000 USD, with at least 51% coming from my own sources. This involved collecting various certificates and some creative solutions. The administrative process was demanding, requiring repeated applications and finding available embassy appointments. In the end, everything worked out, but it was quite an experience.
Jiří Fujera adjusting optical components. Photo: Sankarsh Rao
What is your focus during the two-and-a-half-month internship?
In Professor Carmen Guerra-Garcia’s group, I am working on plasma-assisted combustion in a methane-air mixture. My primary task is to perform optical emission diagnostics of plasma in their existing experiments, which the local team had not previously focused on. Their main interest so far has been studying plasma effects on combustion or combustion products rather than on the plasma itself. Thus, I am conducting optical measurements, helping the team analyze data, preparing a joint article, and trying to lay the groundwork for future collaboration between our teams.
What methods do you use for plasma diagnostics?
I use optical emission spectroscopy, which, simply put, involves collecting light from the plasma using an optical fiber and analyzing its spectrum. From the spectrum, I then determine various plasma parameters, such as temperature or the presence of different products. I also measure electrical characteristics of the plasma, like voltage and current, which, among other things, enables us to determine the energy deposited into the plasma. Over time, we will add analysis of the composition of the output gas. Experimental work, especially in this early phase of my internship, brings common complications—equipment failures, the need to purchase additional equipment, and improvisations in the laboratory. Nevertheless, we have already obtained the first data.
How do you perceive the importance of international cooperation?
Currently, I represent the first concrete step toward future collaboration with MIT. Historically, some cooperation existed, but now a new chapter is opening. If our work proves useful, we would like to establish not only joint publications but also longer-term projects.
Characteristic emission spectrum of a discharge in air and in an air–methane mixture (in a 9:1 ratio). Presence of emission bands of nitrogen and the CH radical. Author: Jiří Fujera.
What brought you to plasma physics?
I have always been fascinated by space and physics, but also by history. When it came down to making a decision, I chose to dedicate myself to physics as a profession and keep history as a hobby. Generally, I prefer working in smaller teams and appreciate the flexibility compared to large projects (which is also why I eventually moved away from fusion research).
Jiří Fujera in the laboratory preparing for experiments. In the background, the head of the laboratory, Carmen Guerra-Garcia.. Photo: Sankarsh Rao
What do you recommend to everyone preparing to go abroad?
I primarily recommend that students start preparing for their international internship early, carefully study visa and financial requirements, and be prepared in advance for administrative complications. It is not a pleasant feeling to find out that the earliest available appointment for an embassy interview is just a few days after your planned departure.
What are your plans after returning from the internship?
The immediate plan is to present the results of this internship at the CESPC conference in Romania, where I will fly the day after returning from the USA. After coming back, I want to finish writing the articles I have in progress and, above all, pass the state exams that I have been postponing a bit. I will also be supervising a bachelor’s student.
Thank you for the interview.
