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Plas@Par: plasmas in all their forms

Whether fundamental or applied, research on plasmas is taking on increasing importance and the Sorbonne University Plas@Par (Plasmas in Paris) Labex is one of the flagships for this. Chantal Stehlé, its director, and Xavier Fresquet, its project leader, explain.

Visuel

For non-specialists, the term plasma does not mean a great deal. Can you explain it for us?

Chantal Stehlé, director of Plas@Par: 99% of all known matter in the universe is in a plasma state. We find plasma in stars, such as the Sun, in nebula, solar wind, polar auroras and even on Earth, such as in lighting and flames. Not all plasmas are natural. Some are created by humans to satisfy numerous industrial applications: for example, fluorescent tubes or the manufacturing of electronic circuits.

Matter is composed of atoms (each atom being formed of a nucleus around which electrons move) and molecules (a group of atoms). When matter becomes plasma, some electrons detach themselves from the nucleus of the atoms and move freely. Matter therefore contains ions (atoms having lost one or more of their electrons), which are positively charged, and electrons, which are negatively charged. Therefore, it reacts strongly with magnetic or electric fields, which gives it specific characteristics.

What challenges are there with research on plasmas?

Xavier Fresquet, Labex project leader: Plasma physics obeys specific rules, different to the ones for solid-state physics for example, and which are still poorly understood. Moreover, plasmas have many possible applications: in the environment, medicine, aeronautics, energy, etc. It is therefore a major challenge in fundamental research as well as applied research. Plas@Par covers both of these aspects and it is an advantage; advancing the understanding of the physical properties of plasmas also enables progress to be made in their applications.

What are the other advantages of the Labex?

C. S.: Plasmas were already a field of excellence at Sorbonne University’s UPMC, which was the initiator of the Labex and which leads it; UPMC is part of the tutelage of nine of the twelve laboratories involved in the project. The creation of Plas@Par has enabled it to enrich its understanding via other French centers and form a center of 140 researchers who cover the different types of plasmas and, above all, unify the different teams to make them work together.

X. F.: The Plas@Par researchers come from several disciplines: physics and astrophysics, chemical physics, applied mathematics and engineering. By combining their skills, they are able to think about realizing very ambitious projects: for example, the construction of a high performance X-ray spectrometer by the Laboratory of Physical Chemistry - Matter and Radiation together with the Paris Institute of Nanoscience.

What type of innovative research has led to these interactions?

C. S.: In fundamental research, the Laboratory’s experts in plasmas generated by laser for the use of intense lasers and the Laboratory’s experts in astrophysical plasmas studying radiation and matter in astrophysics and atmospheres have, for example, collaborated to reproduce the plasma from stars in a laboratory in order to study it. The objective was to understand the origins of very violent stellar jets which are produced during the formation of a star and the role of the ambient magnetic field in this phenomenon.  For this, the team produced a plasma which was representative of that from young stars and subjected it to a high intensity external magnetic field. This was a first. Since then, this type of experience has set a precedent and has spawned a great deal of spin-off research.

And in applied research?

C. S.: In particular, the Labex has given a real boost to three developing research areas. The first is space propulsion. Researchers in the Laboratory of Plasma Physics and the Office national d’études et recherches aérospatiales (the French national aerospace research center) are working on propulsion technology using plasma which would, for example, enable a satellite to be put into space and kept in the desired orbit. In June 2016, this fuel efficient process gave rise to the creation of a start-up: ThrustMe, led by a female researcher from the Laboratory of Plasma Physics and which will produce propulsion engines of this type. 

The second area is in the use of small plasma discharges for therapeutic purposes, for throat cancer in particular and soon for skin cancer. Plasma constitutes a new approach likely to succeed where more traditional treatments (chemotherapy) have a mixed success rate. In vitro experiments have already been conducted and the in vivo phase is providing encouraging results.  This interdisciplinary research is being conducted by the Laboratory of Plasma Physics, the Laboratory of Biomedical Imaging and the Center for Immunology and Infectious Diseases at the Pitié Salpêtrière Hospital. 

What is the third area of research?

X. F.: It is about a new way of fighting against the greenhouse effect linked to certain gases (for example, carbon dioxide and methane) which is being explored by the Laboratory of Plasma Physics and a specialized center in mechanics and engineering: the Jean Le Rond d’Alembert Institute. These two laboratories, whose expertise are complementary to each other, are studying a process of combining plasma and a catalyst to convert molecules of CO2 into raw materials for energy storage and green chemistry. 

To boost this research, the teams were invited to submit a joint European PhD project on recycling CO2 as part of the EU’s Horizon 2020 project. The idea would be to bring the best laboratories for plasmas and catalysts in Europe together to make fifteen PhD students work simultaneously on complementary subjects, each under the joint supervision of the two institutions. 

Apart from funding for the theses and post doctorates on plasmas, what training is being provided by Plas@Par?

C. S.: Previously, there were two second year master’s pathways in plasma physics, involving the UPMC and other French institutions. Since the beginning of the 2015 academic year, they have been grouped into the same pathway, called Plasma and Fusion Physics. The Labex encouraged merging the two in order to streamline training, give more visibility to the master’s program and attract the best students. 

Each year, we also fund two mobility grants to welcome international students into the second year master’s program. Here once again, it is about attracting the best students who will then be ambassadors for the master’s program and this Labex. 

But what we are doing does not stop at future plasma experts. We are looking to raise awareness in a much wider audience about the importance of plasma physics, which, at the moment, is little taught before the master’s stage. 

How can you reach this audience?

X. F.: We are organizing an international summer school for third year undergraduate and first year master’s students in physics or chemistry. At this level, they have generally never heard of plasma physics. The objective is to let them discover the different types of plasmas. The number and quality of candidates are steadily progressing. In 2016, we received a lot of applications from students coming from leading European institutions in the field of plasma and even from American universities.  Proof that we make for an attractive offer! 

The next step will be to expand this awareness to secondary education. We would like to offer students preparing for the CAPES and Agrégation  in physics and chemistry teaching qualifications a training seminar on plasma physics: quite a simple module with public works able to be directly reproduced in secondary schools which would enable them to give their pupils some basic knowledge about plasmas. 

What are you doing to make Plas@Par research more valued in the industry?

C. S.: Each year, we organize an Industry Day. This brings together manufacturers, who explain their issues with plasmas, and Labex researchers, whose works are likely to solve the issue. 

We also invite master’s students, PhD students and post doctorate students to attend. It is a way of raising awareness of R&D in industry, which is even more important as job prospects in academic research are becoming increasingly limited. 

For the same reason, we are raising awareness of student entrepreneurship. This year, for example, we would like to offer them a seminar over several days on creating a start-up, alongside SATT Lutech, other Labex partners and Sorbonne University’s Central Paris Pépite.

The Plas@Par project will be completed in 2019. How could the project be expanded?

C. S.: That is something we have been thinking about. We have put a working group in place to think about what happens after the Labex: what are the areas to continue supporting, the subjects that are rapidly expanding or the ones which are developing and will need to be pushed? How will this be done? And, of course, with what funding?

Related to the article

For reference 

 > The Plas@Par Website

TO WATCH

 > An Allodocteurs video on the project using plasmas for medical purposes supported by Plas@Par. 

 > Two photos of PhD students funded by Plas@Par:

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