Researchers from the University of Tokyo, alongside international collaborators, have made significant strides in understanding solar ejections, a phenomenon that can disrupt both space-based and terrestrial electronic systems. Using a novel approach, they have successfully tracked the evolution of solar ejecta clouds, known as coronal mass ejections (CMEs), through the solar system. This breakthrough could pave the way for improved space-weather forecasting.
Solar storms, particularly CMEs, are more common than many realize. When these storms are detected near Earth, satellites are often put into a protective low-power mode to avoid damage. However, much like unpredictable terrestrial weather events, unforeseen solar storms can cause significant disruption. Researchers are now focusing on understanding how CMEs evolve after leaving the sun, employing a new methodology that leverages data from multiple scientific satellites.
Tracking Solar Eruptions: A New Approach
For the first time, scientists have utilized multiple space-based instruments to make high-quality measurements of an evolving solar ejecta cloud. According to Ph.D. researcher Gaku Kinoshita from the Department of Earth and Planetary Science, this method involves tracking drops in cosmic rays—high-energy particles that constantly bombard the solar system—as a way to monitor the path of solar eruptions.
“Understanding how huge clouds of solar material travel through space is essential for protecting satellites, astronauts, and even power grids on Earth,” said Kinoshita.
The researchers’ technique relies on the Forbush decrease effect, where a CME’s strong magnetic field deflects cosmic rays, allowing scientists to interpret the CME’s physical structure and its changes over time.
The Role of Cosmic Rays and Spacecraft Observations
In March 2022, a rare alignment of three spacecraft—the European Space Agency’s Solar Orbiter, ESA and Japan Aerospace Exploration Agency’s BepiColombo, and NASA’s Near Earth Spacecraft—enabled researchers to observe the same solar eruption from different vantage points. This alignment provided a unique opportunity to compare the event’s appearance from various angles and distances from the sun.
“By combining cosmic-ray data with magnetic-field and solar-wind measurements, we could link changes in the particle signal directly to the physical structure of the eruption,” explained Kinoshita.
This innovative approach demonstrates that even instruments not originally designed for scientific research can yield valuable data. For instance, a simple system-monitoring instrument on the BepiColombo spacecraft was repurposed to detect cosmic-ray decreases, showcasing the potential of overlooked data.
Implications for Future Space-Weather Forecasting
While advanced instruments for direct CME monitoring exist, their operational periods are limited. The new method, however, leverages general instruments that are continuously active, offering a constant stream of data. By integrating data from multiple spacecraft, researchers can construct a three-dimensional picture of CMEs, enhancing the quality and scope of their observations.
“With many spacecraft now operating between the sun and Earth, and more planned for the future, the chances of making routine multipoint observations are increasing,” said Kinoshita.
This development represents a significant step forward in space-weather forecasting. By continuing to combine data from various missions and utilizing all available instruments, scientists aim to achieve a comprehensive understanding of how solar ejections propagate through space.
Looking Ahead: The Future of Space-Weather Research
The ability to predict and understand solar weather is crucial for safeguarding technology and infrastructure on Earth. As more spacecraft are deployed and methods refined, the potential for routine, accurate space-weather forecasts becomes increasingly feasible. This advancement not only protects existing technology but also supports future space exploration endeavors, ensuring the safety of astronauts and equipment alike.
As researchers continue to refine their techniques and expand their datasets, the path to reliable solar weather forecasts becomes clearer, promising a future where the impacts of solar storms can be anticipated and mitigated effectively.
