A vital aspect which they looked at was the "critical height" of the Active Regions, which is the height at which the magnetic field becomes unstable and can lead to a CME. "By measuring how the strength of the magnetic field decreases with height, we can determine this critical height," said lead researcher Harshita Gandhi, a solar physicist at Aberystwyth University. "This data can then be used along with a geometric model which is used to track the true speed of CMEs in three dimensions, rather than just two, which is essential for precise predictions."
She added: "Our findings reveal a strong relationship between the critical height at CME onset and the true CME speed. "This insight allows us to predict the CME's speed and, consequently, its arrival time on Earth, even before the CME has fully erupted." When these CMEs hit the Earth they can trigger a geomagnetic storm which is capable of producing stunning aurorae, often referred to in the northern hemisphere as the Northern Lights. But the storms also have the potential to disrupt vital systems we rely on daily, including satellites, power grids, and communication networks, which is why scientists worldwide are working hard to improve our ability to better predict when CMEs will hit Earth. This requires knowing a more accurate speed of the CME shortly after it erupts from the Sun to better provide advance warnings of when it will reach our planet. Accurate speed predictions enable better estimates of when a CME will reach Earth, providing crucial advance warnings.
"Understanding and using the critical height in our forecasts improves our ability to warn about incoming CMEs, helping to protect the technology that our modern lives depend on," Gandhi said. "Our research not only enhances our understanding of the Sun's explosive behaviour but also significantly improves our ability to forecast space weather events. "This means better preparation and protection for the technological systems we rely on every day."