Glossary

Canton of Vaud

The Swiss canton whose capital is Lausanne, as Article 4 of its constitution of 14 April 2003 states. At the end of 2025 it had 864,226 inhabitants. Read more →

Central solenoid

The coil in the hole of a tokamak’s ring that induces and maintains the electric current in the plasma, working like the primary winding of a transformer. In ITER it can drive a plasma current of 15 megaamperes. Read more →

Deuterium–tritium fusion D–T

The fusion reaction researchers consider easiest to achieve on Earth: two kinds of hydrogen, deuterium and tritium, produce a helium nucleus and a neutron, which carries most of the energy. Deuterium can be extracted from water; tritium is rare in nature and is meant to be produced inside the reactor from lithium. ITER gives the temperature needed as 150 million °C. Read more →

Divertor

The part of a tokamak to which the edge of the plasma is led away so that its heat and particles are absorbed at a distance from the hot core. This keeps impurities out of the plasma; a plasma that touches a limiter directly suffers from more impurities and poorer confinement. Read more →

Electron cyclotron resonance heating ECRH

Heating a plasma with high-power microwaves tuned to the frequency at which electrons gyrate in the magnetic field, so that the electrons absorb the energy and pass it to the ions in collisions. TCV can use up to seven steerable beams, which can also drive a current locally. Read more →

Electronvolt eV

A unit of energy: the kinetic energy an electron gains in passing through a potential difference of one volt in vacuum, 1 eV = 1.602 176 634 × 10⁻¹⁹ J. Plasma physicists often give particle temperatures in it, as in TCV’s electron temperature of 18 keV (kiloelectronvolts) in 2002. Read more →

EPFL École polytechnique fédérale de Lausanne

The Swiss Federal Institute of Technology in Lausanne, a federal institute since 1 January 1969, with its main campus on the lakeside in Écublens. In autumn 2025 it had 14,072 students. Read more →

ETH Domain

The group of Swiss federal institutions made up of two Federal Institutes of Technology, ETH Zurich and EPFL, four research institutes – PSI, WSL, Empa and Eawag – and the ETH Board as its strategic management body. Read more →

Euratom European Atomic Energy Community

The European community for nuclear energy, whose research programme covers European fusion research. Switzerland was not associated with it from 2021 to the end of 2025; under an agreement signed on 10 November 2025, its association applies retroactively from 1 January 2025. Read more →

EUROfusion

The European consortium of national fusion laboratories and universities that runs Europe’s fusion research programme. Its experimental programme uses four medium-sized tokamaks, among them TCV; the Swiss Plasma Center, which represents Switzerland, joined it in 2014. Read more →

Fusion for Energy F4E

The European agency that supplies Europe’s share of ITER. Switzerland took part through F4E from 2007, was out from 2021 to the end of 2025, and has again been a member since 1 January 2026. Read more →

Fusion gain factor Q

The ratio of the fusion power a plasma produces to the heating power delivered to it. No magnetic confinement experiment has yet reached Q = 1; the record, 0.67, was set by JET in 1997, and ITER is designed for Q = 10 (status as of 3 November 2026). Read more →

ITER

The large international fusion experiment, a tokamak under construction in Cadarache in southern France. It is designed to produce 500 megawatts of fusion power from 50 megawatts of heating, a tenfold return, but it will not turn that heat into electricity. Read more →

Lake Geneva Lac Léman

The lake on whose north-eastern shore Lausanne lies; the French call it the Léman. From the shore the city climbs more than 500 metres to the forests of the Jorat, with the Alps across the water. Read more →

Neutral beam injection NBI

Heating a plasma by firing fast atoms into it. Ions are accelerated and then neutralised, because only neutral particles can cross the magnetic cage; inside the plasma they pass on their energy in collisions. On TCV two injectors heat the ions. Read more →

Nuclear fusion

A reaction in which two light atomic nuclei join to form a heavier one. The products weigh slightly less than the nuclei that went in, and the missing mass is released as energy. Fusion is what makes the Sun shine. Read more →

Olympic Capital

The title Lausanne formally received in 1994. The International Olympic Committee moved its headquarters from Paris to Lausanne in 1915; the Olympic Museum opened in 1993 and Olympic House, the present headquarters at Vidy, in 2019. Read more →

Plasma

A state of matter in which the electrons have separated from the atomic nuclei, so the gas is a mixture of charged particles. Fusion fuel becomes a plasma at the temperatures needed for fusion; the hot plasma inside a tokamak weighs just a few grams. Read more →

Poloidal field coils shaping coils

Ring-shaped coils around a tokamak that shape the plasma’s cross-section and help keep it away from the walls. ITER has six; TCV, built to vary the plasma shape, has sixteen. Read more →

Snowflake divertor

A divertor configuration in which two points where the magnetic field cancels out are brought together, spreading the plasma exhaust over more of the wall. It was first produced experimentally on TCV in 2008. Read more →

Stellarator

A ring-shaped fusion device in which the whole twisted magnetic cage comes from external coils, with no current driven around the plasma, which makes it suited to continuous operation. The idea dates from 1951 (Lyman Spitzer); the largest stellarator is Wendelstein 7-X in Greifswald. Read more →

SULTAN superconductor test facility

The Swiss Plasma Center’s facility for testing superconductors for fusion magnets, operating at the Paul Scherrer Institute in Villigen since 1992. It tests conductors in fields of up to 11 tesla with currents of up to 100 kiloamperes, and the SPC calls it the reference facility for ITER superconductors. Read more →

Superconductor

A material that carries electric current without any resistance when cooled to very low temperatures. The largest fusion machines need superconducting magnets, because copper coils could not deliver the field efficiently; ITER’s are made of niobium-tin or niobium-titanium cooled with helium to about 4 kelvin. Read more →

Swiss Plasma Center SPC

EPFL’s centre for plasma physics and fusion research, part of its School of Basic Sciences, which runs the TCV tokamak. It grew out of a Plasma Physics Laboratory set up in 1961, known from 1968 as the CRPP, and took its present name in 2015. Read more →

TCV Tokamak à Configuration Variable

The tokamak of the Swiss Plasma Center in Lausanne, with a vacuum vessel three times taller than it is wide and sixteen shaping coils, built to give its plasma many different shapes. Its first plasma came in November 1992; it is one of the four medium-sized tokamaks in EUROfusion’s programme. Read more →

Tesla T

The SI unit of magnetic flux density, equal to one weber per square metre. For scale: TCV’s toroidal field reached up to 1.54 T (figure of 2007), and ITER’s toroidal field coils have a maximum field of 11.8 T. Read more →

Tokamak from a Russian acronym

A fusion device in which the plasma is held in a ring-shaped (toroidal) vacuum chamber by magnetic fields from surrounding coils and from an electric current flowing in the plasma itself. EUROfusion calls it the most advanced and best investigated fusion device design available today. Read more →

TORPEX

A device of the Swiss Plasma Center for basic plasma physics, in use since 2003: a simple magnetised torus with a major radius of 1 metre. Its cool, thin plasma lets researchers study turbulence and instabilities in detail. Read more →

Triangularity

A number describing how pointed the D-shaped cross-section of a tokamak plasma is. With negative triangularity the D is turned round, its point facing the centre of the machine; the SPC reports that this shape suppresses turbulence. On TCV it could range from −0.7 to 1 (figures of 2007). Read more →

University of Lausanne UNIL

Lausanne’s university, which traces its origins to the Académie founded in 1537 and became a university in 1890. It has seven faculties, and from 1970 it moved to Dorigny, on the lakeside next to today’s EPFL. Read more →

Sources checked on: 3 November 2026