In the third quarter of 2023, the key plasma parameters and performance of the high pulse generator of SUNIST-2 spherical tokamak, a fusion experimental device designed by Tsinghua University and jointly constructed by Startorus Fusion and Tsinghua University, doubled compared with the previous quarter, and several indicators such as the toroidal magnetic field have topped domestically and reached the third place globally in the field of spherical tokamak; the company has also made significant progress in multiple fields, including the industrialization of high-temperature superconducting magnets, digital twins technique of the tokamak as well as fusion-derived technologies.
A number of technological breakthroughs have completed stage-by-stage experimental verification for Startorus Fusion's next step to independently build a fully high-temperature superconductor-controlled fusion device, and at the same time further consolidates Startorus Fusion's competitive advantage as a company among the first rung of the world's commercial fusion energy enterprises.
Plasma current is the key index of tokamak, and the stronger the plasma current, the better the performance of plasma confinement. After obtaining a plasma current of over 100 kA in the first plasma stage in the previous quarter, the plasma current of SUNIST-2 exceeded 220 kA in the third quarter of 2023 without problem (further enhancement had to be actively halted due to the fact that the heat-resistant protection plate in the vacuum chamber had not yet been installed), and the plasma discharge time was significantly prolonged more than doubled, with the experimental results waveform as shown below. The significant enhancement of plasma parameters and rapid iteration speed together is the concrete manifestation of Startorus Fusion's excellent technical route, operation level and iterative development capability.
Fig 1 Comparison of Plasma Current Waveforms
In addition to the significant progress in plasma experiments, Startorus Fusion is also continuing its fusion engineering at a blistering pace.
First of all, Startorus Fusion has successfully upgraded the toroidal magnetic field power supply and coil of SUNIST-2, with the performance more than doubled compared with its first round of discharge, and is now working at a stable 80 kA. Besides, the toroidal magnetic field at the magnetic axis of SUNIST-2 has reached 0.72 T, which is the first in China and the third in the world in the current spherical tokamak.
Fig2. Comparison of current waveforms
The construction of several sets of poloidal magnetic field power supplies for plasma AI control has been completed, with a current-controlling capability of more than 1 kA/ms and a response speed of 10 kHz, which, combined with the high-performance AI and its control algorithms that are being rapidly promoted, will realize high-speed and precise control of various forms of plasma under a variety of complex working conditions.
Second, in terms of high-temperature superconducting magnets, Startorus Fusion has completed the engineering design of the first surface of the fusion-grade spherical tokamak toroidal magnet, and it is a high-level magnet that can fully demonstrate the features of high-temperature superconducting materials, with a size of more than 3 meters. In the process, the team has formed a set of better analysis, design and optimization methods for high-temperature superconducting magnets in terms of electromagnetism, heat and force, and sub-systems and tasks such as cryogenics, winding and testing are being carried out underway orderly, while a number of other special-purpose high-temperature superconducting magnets are being processed.
Fig3. The first surface of toroidal magnets to test
Fig4. Compact Helmholtz Coils for Plasma Sources
At the same time, Startorus Fusion has built a tokamak digital twin system for SUNSIT-2, installing thousands of various types of sensors and actuators closely related to the operation of the device. The company built all-around underlying drivers for these sensors and actuators based on multiple industrial communication protocols, and an industry-standard IoT data storage, access and management system, which, combined with a three-dimensional visualization interface, intuitively and comprehensively displays and records the real-time status of all components of the tokamak, as well as its ancillary equipment and instrumentation., so as to provides solid and convenient safeguards for the efficient and stable operation of SUNIST-2.
Fig5. The Interface of the First Digital Twin System
In order to create more convenient access to experimental data and make full use of the internal 10Gb network, the company has developed a massive data visualization platform purely based on HTML5.0 technology without plug-ins. Through dynamic sampling and other technologies, performance issues such as failure in synchronous dragging and scaling of massive data in multiple canvases were solved, and R&D personnel can get quicker access to the experimental data anytime and anywhere through various terminals using browsers.
Fig6. Web-based Data Visualization Platform
In addition, the industrialization of fusion-derived technologies is also accelerating. Startorus Fusion has recently developed a high bandwidth and high isolation signal isolation amplifier module, with a bandwidth of more than 50MHz and an isolation voltage of over 3kV, which is suitable for the measurement of weak signals at different potentials, in particular for the acquisition of high-precision and high-frequency diagnostic signals under the occasions of serious common mode interferences, such as plasma. The module is flexible and easy to use, can be battery-powered as well as an external power supply, and can also be combined to form a multi-channel isolation amplifier array. The module has already formed a standardized product, being supplied to the relevant laboratories of domestic famous universities. Isolation amplifier modules with various bandwidths, higher isolation voltages, and those suitable for more application scenarios are under continuous development. This signifies that Startorus Fusion's fusion technology has moved from the laboratory to the stage of scenario application and commercial promotion.
In the recent year, Startorus Fusion Energy has laid out more than 70 patents, a complete and rigorous touch upon all the sub-systems involved in fusion energy, including power supply system, control system, magnet system, diagnostic system, host engineering, and overall operation.
Since its founding in October 2021, Startorus Fusion has been committed to the commercial application of fusion energy and related technology research and development. Startorus Fusion has made its mission the completion of China's first commercially controlled fusion reactor, and has focused on miniaturized, commercialized, and rapidly iterative controlled fusion energy devices, and has always been an industry leader in terms of technology level, device parameters and team strength.
In terms of technology and engineering, in 2022, Startorus Fusion, together with the Department of Engineering Physics of Tsinghua University and Institute of Plasma Physics of Chinese Academy of Sciences (ASIPP), completed the assembly of the SUNIST-2 spherical tokamak mainframe in a fast and precise manner and formed a series of new methods or patents but not limited to the ultra-high vacuum sealing, ultra-low resistance detection of the high-current joints, and the position and vibration measurement and analysis.
In July this year, the SUNIST-2 spherical tokamak was completed and carried out its first round of operation, obtaining the first plasma. This is the spherical tokamak with the strongest magnetic field and the highest plasma performance in China at present.
In terms of the SUNIST-2 spherical tokamak, Startorus Fusion plans to heat the plasma to 1.5 keV (about 17 million degrees Celsius) through a repeated reconnection scheme, which will validate the feasibility of the principle of Startorus Fusion's controllable fusion scheme and push the plasma parameters to the advanced level of the world's devices of the same scale. The doubling of the power supply performance this quarter means that Startorus Fusion has taken another solid step towards its goal, and is expected to complete the experimental verification milestone early next year.
Startorus Fusion has also built a versatile team consisting of personnel from fusion science, engineering technology, basic technology and support departments. The core R&D staff of SUNIST comes from the fusion team of the Institute of Nuclear Energy, Department of Engineering Physics, Tsinghua University, which has been operating the first spherical tokamak device (SUNIST) in China for nearly two decades and has accumulated profound experience in spherical tokamak and its technology.
The rapid growth of Startorus Fusion has benefited from the support of the governments at all levels in Shaanxi Province. As of the third quarter, the company has declared and been approved for the following projects: national high-tech enterprises, two-chain fusion, new R&D institutions, Xi'an Talent Program, Nezha enterprises, Shaanxi Provincial Listed Reserve Enterprises, innovative and entrepreneurial talents, Qin Chuangyuan Talents, local-level leading talents, overseas talents, and R&D expense subsidy policy for settled science and technology-based enterprises. All these projects above have accumulated more than 5 million yuan in government awards and subsidies. As Startorus Fusion grows into a global top fusion energy technology enterprise integrating R&D, design, operation and maintenance, the team will continue to be driven by innovative technology, keep breaking through engineering limits, and accelerate towards the goal of "fast and economical realization of fusion energy".
