Researchers at Embry-Riddle Aeronautical University have made a breakthrough in understanding “space waves,” which could ultimately result in more accurate space-weather predictions and safer satellite navigation through radiation belts.
The Earth’s magnetic tilt, which changes seasonally and daily, can trigger variations in large-wavelength space waves called Kelvin-Helmholtz (KH) waves. These waves occur at the boundary between the solar wind (plasma streaming from the Sun at up to 1 million miles per hour) and the Earth’s magnetic shield. KH waves are more frequent during spring and fall, while they are less active during summer and winter.
As the solar wind interacts with the Earth’s magnetic shield, it generates massive KH waves that can reach up to 15,000 kilometers high and 40,000 kilometers long. These waves allow solar wind plasma particles to enter the magnetosphere, causing fluctuations in radiation belt fluxes of energetic particles.
According to Dr. Shiva Kavosi, the first author of the study, these fluctuations can affect astronaut safety and satellite communications and potentially impact power grids and Global Positioning Systems on Earth. “Through these waves, solar wind plasma particles can propagate into the magnetosphere, leading to variations in radiation belt fluxes of energetic particles—regions of dangerous radiation—that may affect astronaut safety and satellite communications,” says Dr. Kavosi, a research associate at Embry-Riddle, in a media release.
Understanding the properties and mechanisms behind these space waves is crucial for forecasting space weather, which represents an increasing threat. Kavosi says that any progress made in understanding the mechanisms behind space weather disturbances will improve their ability to provide forecasts and warnings.
Previously, researchers suggested several different hypotheses to explain the causes of seasonal and diurnal variations of geomagnetic activity, such as the Russell-McPherron (R-M) effect. This study, however, shows that the R-M effect is not the only explanation for seasonal variations in geomagnetic activity. “Equinox-driven events, based on the Earth’s dipole tilt, and R-M effects could operate simultaneously,” notes Dr. Katariina Nykyri, professor of physics and associate director for the Center of Space and Atmospheric Research at Embry-Riddle.
In the future, constellations of spacecraft in the solar wind and magnetosphere could help researchers better understand the complex, multi-scale physics of space weather phenomena. Nykyri believes that such a system would allow advanced warnings of space weather events, which could be useful for operators of rocket launches and electrical power grids. The research could also be a step forward in ensuring the safety of astronauts and satellites.
The findings were published in the journal Nature Communications on May 4, 2023.