The Institute for Plasma Research (IPR) in India has successfully commissioned its first spherical tokamak, achieving first plasma in the new device. The milestone, detailed in a recent preprint, was reached using a modest Ohmic heating system augmented by a 2.45 GHz microwave system for plasma initiation. This achievement follows the completion of major mechanical, magnetic, and electrical integration of the compact machine. An initial suite of diagnostics, including visible imaging, spectroscopy, magnetics, and radiation monitors, was used to confirm and characterize the initial plasma shots. The entire operation is managed by a centralized control and data acquisition system. Source: arXiv

The new spherical tokamak is intended to serve as a low-cost experimental platform to explore physics phenomena specific to low-aspect-ratio configurations. According to the commissioning report, its primary research goals include studies on non-inductive startup, current drive in overdense plasmas, and shaped plasma physics. These research areas are critical for developing the scientific basis for future compact fusion reactors. The device complements IPR's existing high-aspect-ratio tokamaks, ADITYA-U and SST-1, by providing access to a different and important operational regime within the broader tokamak research landscape. Source: arXiv

The new spherical tokamak is intended to serve as a low-cost experimental platform to explore physics phenomena specific to low-aspect-ratio configurations.

Spherical tokamaks (STs) are a distinct class of magnetic confinement devices characterized by a nearly spherical plasma shape and a low aspect ratio—the ratio of the major radius to the minor radius. This geometry allows for operation at higher plasma beta (the ratio of plasma pressure to magnetic pressure) compared to conventional tokamaks, suggesting a more efficient use of the magnetic field. The physics of STs, particularly regarding stability and confinement, is an active area of global research. This new machine at IPR joins a family of devices worldwide dedicated to advancing the spherical tokamak concept as a potential pathway to commercial fusion energy. Source: arXiv

The commissioning process involved a series of integrated tests on the coil systems before the first plasma experiments were attempted. The successful integration and operation of the magnetic and electrical systems represent a significant engineering accomplishment for the IPR team. While the initial preprint does not provide specific plasma parameters such as temperature, density, or confinement time from these first shots, the successful machine startup is the foundational step required before beginning systematic physics experiments. Future work will focus on characterizing the plasma and commencing the planned research campaigns on this new government-funded platform. Source: arXiv