Solar flares: U-M experts highlight gaps preventing accurate predictions of impacts around Earth


The recent spike of activity from the sun occurred during what NASA has dubbed the Heliophysics Big Year-a celebration of solar science centered on the April 8 total eclipse, the last that will be visible from the continental U.S. for 20 years.

University of Michigan experts on space weather and solar physics are available to discuss how well the impacts of such flares on Earth can be predicted and what is needed to improve those predictions.

U-M has had a leading role in developing the models currently used by the national Space Weather Prediction Center to provide regional space weather forecasts for Earth and its surroundings, and the university now leads the NASA-funded $9.7-million Center for All-Clear Solar Energetic Particle Forecast, or CLEAR Center , which aims to forecast harmful solar particle radiation across the solar system.

Last week, the sun emitted three solar flares that reached X class-the highest on NASA and NOAA intensity scales. While disruptions on Earth were minimal, the sun is in a particularly active phase of its 11-year cycle of fluctuating activity.

Solar flares are emissions of radio waves, light, X-rays and gamma rays at the surface of the sun that are often preceded by potentially dangerous eruptions of highly energized streams of plasma particles, called solar energetic particle events, and clouds of plasma and magnetic fields, called coronal mass ejections, or CMEs.

These events can deliver lethal doses of radiation to astronauts working in space, damage the electronics on satellites, disrupt radio and GPS communications on Earth, and cause large power outages on the ground. However, we still don’t fully understand when any particular solar flare at the sun can and will disrupt life on Earth.

Mojtaba Akhavan-Tafti is an assistant research scientist of climate and space sciences and engineering who studies how CMEs change on their way to Earth, potentially impacting their shape, intensity and likelihood of disrupting technology on Earth.

"A day after the incident, NASA and NOAA still could not verify whether there was a coronal mass ejection associated with the X-class flares,- he said. "This is a reminder that we are ill-equipped to detect CMEs and see how they travel through the solar system.

"We currently have the know-how to vastly improve our solar activity detection and prediction capabilities, but we need Congress to approve funding to develop more advanced infrastructure for real-time monitoring of space weather.-

Justin Kasper , professor of climate and space sciences and engineering, is the principal investigator of SunRISE, a NASA mission that aims to get more advanced intel on when harmful radiation from the sun might hit Earth.

"This particular flare wasn’t a particularly disruptive event. It only impacted some daytime radio transmission,- he said. "The rankings that people are talking about refer to how bright the flare is in the x-ray, but that is only one part of how solar activity can hurt us. If a flare creates high-energy particle radiation, that radiation needs to get to Earth to have an impact. If the flare is pointed away from Earth, it can take hours to days for the radiation to reach us. CMEs move slower and take days to reach us. So far, there’s no sign of danger.-

Right before the satellites at Earth detect energetic particles or CMEs, they always detect a very intense radio burst, suggesting that they could be a good early warning signal that a potentially disruptive event is approaching Earth. However, sometimes Earth gets a radio signal from the sun when no eruptions reach Earth. Kasper wants to test if this is due to an inconsistency in the sun’s radio emissions or if it’s only a matter of how the CME is oriented.

"Maybe the times we see the radio bursts without getting the solar-particle radiation is because the CME or solar particle event was pointed away from Earth,- he said. "We want SunRISE to image what part of these eruptions are making those radio bursts so we can understand why the storms make those radio bursts and how they line up with Earth.-

Even if we can see when a CME could hit Earth, it’s hard to know if the CME will have any impact upon its arrival, Kasper said.