The American Dream
Many young scientists dream of spending a few years in the United States. Five PhD students from the CRPP, and in the process of completing their thesis, have returned from an international conference in the U.S. – an opportunity to create contacts for future post-doctorates. We went to meet them.
The CRPP at EPFL recently provided an opportunity for their PhD thesis students to visit a few well-known laboratories, while attending a conference on plasmas. The goal is to create links with the international scientific community, and to identify post-doctorate opportunities abroad. “The CRPP is world renowned, and our students are working on innovative projects at the cutting-edge of research into plasmas”, explains Yves Martin, assistant director at the CRPP. As a result, the big American universities like MIT, Princeton and Wisconsin are enthusiastic about welcoming EPFL PhD students. Five students have just returned from a two- to three-week stay in the United States, where they presented their work to these institutions.
For example, Francesco Piras is working on strange forms of plasma, in particular “snowflakes”. He succeeded in creating, for the first time, this unusual form, which has the capacity to reduce the temperature on the wall of a tokamak and modify the instability of the sides of the plasma – one of the most critical problems for the future nuclear fusion reactors. Princeton University is evidently interested in welcoming a scientist who can master these complex forms.
Theodoros Panis is studying the stability of waves in tokamaks. A plasma in combustion maintains a very high temperature thanks to energy-charged particles produced by fusion reactions (alpha particles), but this procedure is disturbed by the so-called “Alfvén” waves, named after the person who discovered them, Hannes Alfvén. Mr. Panis’ objective is to control the stability of these waves and render them innocuous. The “Fusion” group of General Atomic (San Diego), as well as MIT, were very interested in his profile.
As for Silvano Gnesin, he is currently finishing his PhD, studying high-energy X-rays. He has installed a system consisting of two cameras, enabling the recording from different angles of the areas of plasma that emit these X-rays, which will facilitate the creation of a tomography. MIT uses a similar procedure, but only using one camera, rendering it less performant. Therefore, they showed a genuine interest in this technique. The CRPP, thru Silvano Gnesin, hopes to be able to improve their mastery of this technique, which would enable a better understanding of the emission of X-rays in plasma, a method also used in the study of astronomical objects and in nuclear medicine.
Christian Theiler is studying turbulences at the edge of plasma, and how they move towards the walls. There is actually a “blobs” effect, sort of packets of plasma that escape and can potentially damage the walls of the tokamak. These blobs are also encountered in the earth’s ionosphere, and disturb GPS devices and communication satellites. A better understanding of these “parasites” would enable their prevention and to take the necessary measures (for example, by taking the satellite temporarily off line). Moreover, Mr. Theiler is the author of a law that links speed to the size of blobs. Once more, several American universities are very interested in this student.
Last but not least, Federico Felici is developing methods to control fusion plasmas, to guarantee their performance and stability. The new techniques that he has implemented and tested on the TCV tokamak at the CRPP were highly acclaimed by his American colleagues, who are working on similar approaches. The idea of creating plasma in a fusion machine and, at the same time, simulating this with the help of a computer for monitoring purposes, has in particular created a high level of interest in the “Fusion” group of General Atomics and at Princeton University.
Ambroggio Fasoli, Professor at the CRPP, explains that “the CRPP is working in a spirit of healthy competition, more or less hand-in-hand, to further research in this area. There is no problem of confidentiality if one of our students works with another university.”