Globus-M2 reaches hot-ion conditions near 50 million kelvin
Measurements and modelling in Russia’s Globus-M2 spherical tokamak examine how neutral particle beams and magnetic confinement produce hot-ion plasma. Ion temperatures reached about 50 million kelvin. The peer-reviewed study connects improved heat retention to stronger magnetic fields and rotation-related suppression of turbulence, while instabilities and uncertainty in scaling to other machines remain. The experiments do not demonstrate net energy production.
Science··Evening
Neutral beams heat a compact plasma
Ion temperatures near 50 million kelvin were achieved in Russia’s Globus-M2, a spherical tokamak that uses magnetic fields to confine plasma for fusion research. The peer-reviewed study combined experimental measurements with plasma modelling. Neutral particle beams heated deuterium plasma, bringing ions above 4 kiloelectronvolts. Some experiments supplied the beam early as plasma current increased. Later sawtooth oscillations flattened central temperature and density profiles; a second beam enabled high ion temperatures even as those oscillations continued.[1]
Rotation accompanies better heat retention
A separate analysis selected 300 discharges, focusing on quasi-stationary intervals and excluding large magnetic disturbances. Ion heating was more effective with deuterium beams than with hydrogen beams. Linear gyrokinetic calculations supported an explanation involving the momentum supplied by the beam: changes in rotation speed across the plasma can suppress ion-scale turbulence. The work did not include nonlinear computational verification of this explanation.[1]
Stronger fields face a scaling constraint
Comparison with published results from the ST40 tokamak suggested that confinement gains from increasing magnetic field may saturate. The gap between the two machines complicates predictions for fields lying between them. Future designs must also address the heat lost from plasma and its large-scale instabilities. These short research discharges investigate plasma confinement rather than demonstrate net energy gain or electricity generation. The authors make their experimental data available on request.[1]
