The ULS (UMIST Linear System) is a gas target divertor simulator located on the former

UMIST The University of Manchester Institute of Science and Technology (UMIST) was a university based in the centre of the city of Manchester in England. It specialised in technical and scientific subjects and was a major centre for research. On 1 Oct ...

campus of the

University of Manchester , mottoeng = Knowledge, Wisdom, Humanity , established = 2004 – University of Manchester Predecessor institutions: 1956 – UMIST (as university college; university 1994) 1904 – Victoria University of Manchester 1880 – Victoria Univer ...

. It enables physicists to study the recombination processes of a detached

plasma Plasma or plasm may refer to: Science * Plasma (physics), one of the four fundamental states of matter * Plasma (mineral), a green translucent silica mineral * Quark–gluon plasma, a state of matter in quantum chromodynamics Biology * Blood pla ...

in a

hydrogen Hydrogen is the chemical element with the symbol H and atomic number 1. Hydrogen is the lightest element. At standard conditions hydrogen is a gas of diatomic molecules having the formula . It is colorless, odorless, tasteless, non-toxic, an ...

target chamber. Research on detached plasma and on its recombination modes is of primary importance in order to design an appropriate divertor region in a future

nuclear fusion Nuclear fusion is a reaction in which two or more atomic nuclei are combined to form one or more different atomic nuclei and subatomic particles ( neutrons or protons). The difference in mass between the reactants and products is manifest ...

power plant, where huge amounts of

energy In physics, energy (from Ancient Greek: ἐνέργεια, ''enérgeia'', “activity”) is the quantitative property that is transferred to a body or to a physical system, recognizable in the performance of work and in the form of heat a ...

will be deposited by the fast-moving

particle In the Outline of physical science, physical sciences, a particle (or corpuscule in older texts) is a small wikt:local, localized physical body, object which can be described by several physical property, physical or chemical property, chemical ...

s generated in the main reactor. The major goal of the ULS as for many other linear divertor simulators, is to reproduce the same

temperature Temperature is a physical quantity that expresses quantitatively the perceptions of hotness and coldness. Temperature is measured with a thermometer. Thermometers are calibrated in various temperature scales that historically have relied o ...

and

density Density (volumetric mass density or specific mass) is the substance's mass per unit of volume. The symbol most often used for density is ''ρ'' (the lower case Greek letter rho), although the Latin letter ''D'' can also be used. Mathematical ...

conditions of the SOL ( Scrape Off Layer) of a

tokamak A tokamak (; russian: токамáк; otk, 𐱃𐰸𐰢𐰴, Toḳamaḳ) is a device which uses a powerful magnetic field to confine plasma in the shape of a torus. The tokamak is one of several types of magnetic confinement devices being d ...

in a linear environment and therefore to make easier the study of its properties. In the past few years, ULS has been used with great insight to analyze the molecular activation and the electron-ion recombination modes, and to determine the conditions for their activation: diffusive processes have also been considered. However, research on these subjects is still ongoing and our understanding of the elementary processes involved in a detached plasma is still far from being satisfactory.

References

Further reading