Tokamak Energy announced on February 27, 2018, that its ST40 spherical tokamak achieved a plasma temperature of 100 million degrees Celsius. This temperature is considered a critical benchmark for achieving net energy gain in a fusion reactor, as it is the minimum required for efficient D-T fusion reactions. The experiment was conducted using a hydrogen plasma, and the temperature was measured using Thomson scattering diagnostics. This result represents a significant step forward for the private fusion company's development roadmap.

The ST40 device is designed to operate at high plasma pressures and temperatures, utilizing strong magnetic fields to confine the plasma. Its spherical tokamak configuration offers potential advantages in terms of higher beta values and a more compact design compared to traditional toroidal tokamaks. Achieving 100 million degrees Celsius demonstrates the efficacy of the ST40's magnetic confinement system and its ability to reach conditions relevant for future power-generating fusion devices. This temperature is approximately seven times hotter than the core of the sun.

The ST40 device is designed to operate at high plasma pressures and temperatures, utilizing strong magnetic fields to confine the plasma.

Prior to this announcement, Tokamak Energy had achieved several milestones with its earlier devices, including the smaller ST25 and ST50. The ST50, for instance, had previously reached temperatures of 15 million degrees Celsius. The ST40's design incorporates high-temperature superconducting (HTS) magnets, a technology that Tokamak Energy is actively developing for its future commercial fusion power plants. The successful operation at these extreme temperatures validates the company's approach to magnetic confinement and plasma heating.

This achievement places Tokamak Energy among a select group of fusion research institutions that have reached this plasma temperature threshold. While 100 million degrees Celsius is necessary for fusion, it is not sufficient for net energy production. Future experiments will focus on increasing plasma density and confinement time to achieve ignition and a positive net energy output (Q>1). The company aims to demonstrate a net energy gain in its next-generation device, the ST-HTS, by the mid-2020s.

The ST40's success is a testament to the ongoing progress in private fusion research, complementing large-scale international efforts like ITER. Tokamak Energy's focus on HTS magnets and the spherical tokamak design offers a distinct pathway toward commercial fusion power. The company's roadmap includes further optimization of plasma performance and the development of a prototype power plant. Continued progress in achieving higher temperatures, densities, and longer confinement times will be crucial for realizing fusion energy's potential.

The ST40 device is a key component in Tokamak Energy's strategy to develop compact, high-field fusion energy systems. The company's approach emphasizes rapid iteration and the integration of advanced magnet technology. Achieving 100 million degrees Celsius in a hydrogen plasma is a critical validation of the ST40's design and operational capabilities. This milestone is a significant step towards demonstrating the scientific and engineering feasibility of their fusion power plant concept, which aims to deliver clean, abundant energy.