Spherical Tokamak



The primary objective of this facility is to carry out fundamental physics research on spherical tokamak equilibria, non-inductive plasma start-up and current sustainment, high-beta plasma operation, and wall conditioning techniques. These studies will provide valuable proof-of-principle insights relevant to the development of steady-state tokamak-based fusion reactors.
Beyond research, this tokamak serves as an excellent training platform for the next generation of fusion scientists and engineers. It offers young researchers hands-on experience in tokamak operation, diagnostics, and carry on physics experiments.


First Plasma Day
(Right) Image as captured by a Fast camera of the first plasma. (left) A view of first plasma parameters being observed.

After the first plasma discharge demonstration, the ST team actively started taking plasma discharges and focusing on plasma current formation and sustainment, wall conditioning, loop voltage optimization, and related parameters. The triggering sequence has now been further optimized, with specific focus on the firing sequence of equilibrium field. Various experiments involving wall conditioning, Ohmic breakdown studies, ECR plasma characterization, induced current measurement & its effect on plasma start-up, equilibrium optimization etc have been planned.

Various Sub systems of Spherical Tokamak:
Commissioned Small Scale Spherical Tokamak

Power Supply
Capacitor bank based power supplies:TF ,EF, OT

High Voltage Busbar Routing
Bus bar routings from power supplies to the SS-ST machine and PCS


2.45 GHz ECR system
2.45 GHz ECR system connected to the SS-ST vessel with rectangular waveguide. De-mineralized water Cooling system is installed to cool ECR

Glow discharge cleaning system
Glow discharge cleaning electrode installed on vacuum vessel

Control room

Prototype Center Stack
Center stack in ST device is a challenging engineering due to tight space in the machine bore and accommodating TF inner coil bundle and CS coil with required cooling to form a single housing. A prototype of a CS stack is designed, fabricated and tested successfully at IPR. This shall be useful for the ST device.


Contact for more information:
Name: Dr. Kishore Mishra
Designation: Scientific Officer-G
Email: kmishra@ipr.res.in
Phone No. (extn): 2137