In the quest to harness the power of nuclear fusion, scientists are continually exploring innovative methods to enhance reactor efficiency and fuel utilization. A recent study published in the journal ‘Nuclear Fusion’ (Fusion Nucleaire) offers a novel approach to diagnosing the lifetime of spin-polarized fuel, a critical factor in maximizing fusion power output. The research, led by A. Garcia of the Oak Ridge Institute for Science and Education and Princeton University, delves into the potential of D–D reactions to provide insights into the persistence of nuclear polarization in magnetic fusion experiments.
Spin-polarized fuel holds the promise of boosting fusion power while reducing fuel consumption. The key lies in maintaining the polarization of the nuclei, which can significantly enhance the fusion reaction rate. Garcia’s study investigates whether reactions between an unpolarized deuterium (D) beam and polarized deuterium nuclei can experimentally determine the longevity of this polarization.
The differential cross section for D–D reactions between unpolarized and polarized nuclei varies with polarization, allowing scientists to infer the polarization state by measuring the fusion products. Garcia and his team evaluated this method using 3 MeV proton detection in the DIII-D tokamak, employing 81 keV neutral beams and polarized target fuel injected as a pellet. “The sensitivity of energy-resolved measurements to polarization is a game-changer,” Garcia explains. “It means we can infer the polarization state with a high degree of accuracy, which is crucial for optimizing fusion reactions.”
The study found that the measurement of the escaping proton pitch is insensitive to the degree of polarization, but energy-resolved measurements are highly sensitive. This sensitivity is consistent across different angles of beam injection, making the method versatile and robust. Moreover, the large D–D reaction rate in this scenario ensures that uncertainties associated with counting statistics are minimal, making the inference of polarization feasible with current technology.
The implications of this research are far-reaching. By providing a reliable method to diagnose the lifetime of spin-polarized fuel, Garcia’s work could pave the way for more efficient and cost-effective fusion reactors. This, in turn, could accelerate the commercialization of fusion energy, a long-sought goal in the energy sector. As Garcia puts it, “This method could be a significant step forward in making fusion energy a viable and sustainable source of power.”
The study, published in ‘Nuclear Fusion’, underscores the importance of innovative diagnostic techniques in advancing fusion research. As the energy sector continues to explore sustainable and efficient power sources, breakthroughs like this one will be instrumental in shaping the future of energy production.