The coronal heating problem has baffled astrophysicists for decades. While the Sun’s core is the primary source of heat production, the solar surface, or photosphere, is only about 200 times hotter than the corona, the outermost layer of the solar atmosphere.
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However, a breakthrough discovery suggests that high-frequency magnetic waves may hold the key to understanding why the Sun’s atmosphere is hotter than its surface.
The Solar Enigma
For over 80 years, astrophysicists have grappled with the question of why the Sun’s corona, a region farther from the core, is significantly hotter than its surface. The conventional wisdom suggested that heat should dissipate as it moves outward from the core, but this wasn’t the case with the Sun.
Shedding Light on the Mystery
A team of scientists from the Royal Observatory of Belgium (ROB) and KU Leuven embarked on a mission to uncover the secrets of the Sun’s atmospheric temperature. Their research led to a groundbreaking discovery: high-frequency magnetic waves play a pivotal role in maintaining the Sun’s atmosphere at temperatures reaching millions of degrees.
Magnetic Waves: The Heat Source
Prof. Tom Van Doorsselaere at KU Leuven explained the significance of this discovery, stating, “Magnetic waves have emerged as a compelling factor in heating the corona. Over the past 80 years, astrophysicists have tried to solve this problem, and now more and more evidence is emerging that magnetic waves can heat the corona.”
Observations from Solar Orbiter
The breakthrough findings were made possible by the Extreme Ultraviolet Imager (EUI) telescope onboard Solar Orbiter, a spacecraft operated by the European Space Agency (ESA). This spacecraft, now positioned behind the Sun, provided the critical observations that led to a deeper understanding of coronal heating.
High-Frequency Waves Take the Spotlight
The research team focused on a critical question: Were the high-frequency magnetic oscillations more significant in terms of energy compared to their lower-frequency counterparts? To answer this, they conducted a comprehensive statistical meta-analysis, pooling data from various scientific studies to identify previously undiscovered patterns.
The Conclusive Results
Their conclusion was resounding: high-frequency waves play a more substantial role in the total heating of the Sun’s corona than their low-frequency counterparts. Dr. David Berghmans, the principal investigator of EUI, emphasized the significance of this finding, saying, “Given the key role that fast oscillations play in coronal heating, we will now dedicate substantial efforts to detecting higher-frequency magnetic waves with EUI.”
In conclusion, the mystery of why the Sun’s atmosphere is hotter than its surface has taken a significant step towards resolution. The discovery of high-frequency magnetic waves as a primary contributor to coronal heating sheds new light on this astrophysical puzzle. With the aid of advanced technology and meticulous research, scientists are unraveling the secrets of our nearest star, bringing us one step closer to understanding the enigmatic workings of the cosmos.
Daye Lim, Tom Van Doorsselaere et al. The Role of High-frequency Transverse Oscillations in Coronal Heating. The Astrophysical Journal Letters. DOI 10.3847/2041-8213/ace423