New Discovery of Twisting Magnetic Waves on the Sun

Astronomers using the world’s most powerful solar telescope have discovered a new phenomenon on the Sun: small-scale magnetic twists. This discovery may help solve the long-standing mystery of why the Sun’s atmosphere gets hotter as it extends away from its surface.

Using the Inouye Telescope for Analysis

This discovery was based on data from the Daniel K. Inouye Solar Telescope in Hawaii, which provided the first direct evidence of twisting magnetic movements of energy-packed plasma waves in the Sun’s outer atmosphere, known as the corona. These waves are called Alfvén waves.

The existence of Alfvén waves was first predicted by Swedish Nobel laureate Hannes Alfvén in 1942. They are magnetic disturbances that travel through plasma, the hot, electrically charged gas that constitutes the Sun. While larger versions of these waves had been observed before, the smaller, constantly occurring versions had eluded detection until now.

The Significance of the Scientific Discovery

This discovery marks the end of a long search for these waves, which dates back to the 1940s. Scientists have long believed that these small waves could continuously transfer energy from the Sun’s surface to its atmosphere, fueling the solar wind and heating the corona to millions of degrees, much higher than the Sun’s visible surface temperature of about 5,500 degrees Celsius.

The findings provide crucial confirmation of theoretical models on how magnetic disturbances transfer and dissipate energy in the Sun’s upper atmosphere. Thanks to these direct observations, scientists can now test these models against reality.

Techniques Used in the Discovery

To identify the Alfvén waves, Morton’s team used the Inouye Telescope, which captures the highest-resolution images of the Sun to date. This telescope can detect subtle changes in light that reveal how plasma moves through the corona, allowing scientists to view the Sun in unprecedented detail.

During the telescope’s operational phase in October 2023, the team tracked iron atoms heated to 1.6 million degrees Celsius and observed slight red and blue shifts on either side of the magnetic loops, a hallmark of Alfvén waves.

Future Implications of the Discovery

The results suggest that even in the quietest regions of the Sun, the corona is filled with Alfvén waves. These waves continuously twist the Sun’s magnetic field lines, transferring energy across its layers. They carry energy from the lower atmosphere to the corona, where it is released as heat, offering new insights into why the Sun’s outer atmosphere is hotter than its surface.

For Morton and his colleagues, this long-awaited discovery opens new avenues for investigating how these waves propagate and dissipate energy in the corona.

Conclusion

The discovery of Alfvén waves represents a significant step toward a better understanding of the mechanisms heating the solar corona. Thanks to advanced telescopes and modern techniques, scientists can now study solar phenomena in unprecedented detail, potentially improving theoretical models and our understanding of the Sun’s dynamic nature.