The Factory of the Stars: Helix, fusilli and plasma

In the previous episodes…

Nuclear fusion research is an enterprise where scientists from all over the world collaborate. Padua has a long tradition of research in plasma physics and fusion. The Rfx experiment began in 1991. Over the years Rfx has achieved very important results: on the confinement of plasma, its self-organization processes, on its magnetofluid dynamics stability and on how to control it. More recently, the Neutral Beam Test Facility project began. Nbtf aims to build a 1:1 scale prototype of the Iter neutral particle injector.

In this episode

Put a piece of the sun in a box in order to have an inexhaustible, clean, safe and CO2-free energy source. In the eighth episode of the Factory of the Stars Piero Martin makes us discover one of these special boxes: the Rfx experiment, the largest experiment in the world in the reversed filed pinch configuration based at Consorzio Rfx in Padova. Inside Rfx, plasmas are produced with temperatures of around 15 million degrees centigrade. The Rfx plasmas are studied in detail with a series of diagnostic tools, such as an interferometer based on a laser system, a complex tomography system, magnetic probes. Generations of students and researchers have worked on Rfx, including Piero himself. Two PhD students of the University of Padua mentored by Piero and his colleagues have been awarded the prize for the best doctoral thesis on plasma physics and fusion awarded by the European Physical Society.

Rfx has a different configuration than the tokamak. Rfx is a Reversed field pinch. To the Rfp configuration belong the experiments Mst (Universiy of Wisconsin, Madison), Extrap T2-r (Royal Institute of Technology, Stockholm), Relax (Kyoto Institute of Technology), KTX (University of Science and Technology of China).

Thanks to studies made in Rfx and in other devices it has been understood that in particular conditions the plasma tends to arrange itself following a helical shape, like “fusilli” pasta. Experimentally it has been understood that the best performances are obtained just when the plasma assumes the helical shape. Theoretical physicists have been able to describe the process through numerical simulations. The micro-turbulence within the plasma was also studied, as well as its macroscopic properties of confinement of particles and energy and its magnetofluidodynamic stability. The latter is controlled with a complex feedback system that is based on 192 magnetic coils. This system is one of the most advanced in the world for controlling the stability of magnetically confined plasmas.

The Factory of the Stars, eighth episode: "Helix, fusilli and plasma". Shooting and editing by Elisa Speronello; project manager: Francesco Suman


  1. A sun in the lab to rescue the planet
  2. The engine of the sun
  3. Caps, nuclei and shoeboxes
  4. Very special bottles
  5. Fusion, a safe choice
  6. Science without frontiers
  7. Padova, a tradition of science
  8. Helix, fusilli and plasma
  9. Under control
  10. A Million Volt lighter for Iter
  11. DTT: a made in Italy fusion


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