India Commissions First Spherical Tokamak for Fusion Research

Key facts

• The Institute for Plasma Research (IPR) in Gujarat has commissioned India's first spherical tokamak and begun plasma experiments.
• A spherical tokamak is more compact than conventional doughnut-shaped tokamaks and resembles a hollowed-out apple.
• The first plasma was produced on December 11, 2025, and scientists have since carried out 114 plasma discharges.
• When the magnetic system is switched on, large unwanted electrical currents are induced in the metal walls of the vessel, producing magnetic effects that interfere with the plasma.
• Researchers are exploring ways to compensate for the unwanted current by changing the arrangement of magnetic coils or using additional sources.
• The vacuum inside the machine has improved substantially through regular glow-discharge cleaning to remove gases and impurities from vessel walls.
• The challenge for IPR is to make plasma last longer and remain stable.
• The UK has the Mega Ampere Spherical Tokamak Upgrade (MAST-U), and private company Tokamak Energy is developing the ST40 spherical tokamak.
• Britain is also working on the Spherical Tokamak for Energy Production (STEP), a prototype fusion power plant.
• The US has the National Spherical Torus Experiment Upgrade (NSTX-U) at the Princeton Plasma Physics Laboratory.
• Japan has the Q-shu University Experiment with Steady-State Spherical Tokamak (QUEST).
• China, South Korea, Russia, Italy and Spain also have spherical tokamak research programmes.
• Commercial fusion power could provide large quantities of low-carbon electricity.
• Unlike conventional nuclear fission, fusion does not depend on a chain reaction; if the conditions needed for fusion disappear, the reaction stops.
• The significance of India's spherical tokamak lies in the knowledge and expertise it can build for the future.