Light, the ever-present entity that illuminates our world, has long been a subject of fascination for scientists. From banishing darkness to enabling telecommunications and revealing the unseen, light plays a crucial role in our lives. Now, researchers have made groundbreaking discoveries about photons, the fundamental particles of light, that could potentially aid in the quest for fusion energy.
In a recent study, scientists from the Princeton Plasma Physics Laboratory (PPPL) performed a series of mathematical calculations to explore the basic properties of photons. They found that one of these properties, known as polarization, is topological in nature. This means that the direction of the electric fields surrounding a photon remains unchanged, even as the photon moves through various materials and environments.
Polarization: The Key to Photon Behavior
Polarization, which determines the direction of the electric fields around a photon, has a significant impact on the particle’s behavior. According to basic physical laws, a photon’s polarization influences the direction it travels and limits its movement. Consequently, a beam of light composed solely of photons with a single type of polarization cannot spread into every part of a given space.
Hong Qin, a principal research physicist at PPPL and co-author of the paper published in Physical Review D, emphasized the importance of these findings. “Having a more accurate understanding of the fundamental nature of photons could lead to scientists designing better light beams for heating and measuring plasma,” he said.
Tackling the Complexity of Fusion Energy
While the researchers focused on individual photons, their ultimate goal was to address a larger, more complex problem: harnessing beams of intense light to create long-lasting perturbations in plasma, which could help maintain the high temperatures necessary for fusion.
These perturbations, known as topological waves, often occur at the boundary between two different regions, such as plasma and the vacuum in tokamaks. By gaining a deeper understanding of light, particularly the radio-frequency waves used in microwave ovens, scientists hope to control and create these waves in plasma.
“We are trying to find similar waves for fusion,” explained Qin. “They are not easily stopped, so if we could create them in plasma, we could increase the efficiency of plasma heating and help create the conditions for fusion.”
The researchers also discovered that the spinning motion of photons cannot be separated into internal and external components, unlike objects with mass. This finding challenges the assumptions made by many experimentalists and highlights the need for a better theoretical explanation of light’s behavior.
Eric Palmerduca, a graduate student in the Princeton Program in Plasma Physics and lead author of the paper, emphasized the significance of these results. “These findings mean that we need a better theoretical explanation of what is going on in our experiments,” he said.
As scientists continue to unravel the mysteries of photons, their newfound knowledge brings them one step closer to harnessing the power of fusion energy. With a clearer understanding of light beams and their potential to create beneficial topological waves, researchers at PPPL are paving the way for a greener, more sustainable future.
