Sunrise-III Reveals Intricate Magnetic Structures in Quiet-Sun Regions
- Researchers operating the balloon-borne solar observatory Sunrise-III discovered unexpectedly intricate magnetic structures above quiet-sun regions during its flight in the stratosphere in 2024.
- Quiet-sun regions lack sunspots and cover the vast majority of the solar surface.
- The observatory's instruments mapped fine details of the magnetic canopy.
Researchers operating the balloon-borne solar observatory Sunrise-III discovered unexpectedly intricate magnetic structures above quiet-sun regions during its flight in the stratosphere in 2024. Published in The Astrophysical Journal Letters, the findings reveal thin, elongated magnetic threads embedded within the solar atmosphere, providing fresh data on how energy travels from the solar surface to heat the outer atmosphere.
Stratospheric Balloon Captures Hidden Solar Threads
Quiet-sun regions lack sunspots and cover the vast majority of the solar surface. Yet their weak magnetic fields have historically proved difficult to measure from the ground due to atmospheric blurring. To bypass this interference, the Sunrise-III mission carried a 1-meter telescope to an altitude of 35 kilometers aboard a stratospheric balloon during its 2024 flight. The project is an international collaboration involving multiple countries and research institutes.
Mapping the Intricate Magnetic Canopy
The observatory’s instruments mapped fine details of the magnetic canopy. This canopy forms when magnetic fields concentrated at the solar surface—the photosphere—arc outward into the chromosphere.
Rather than a simple, uniformly expanding layer, the Sunrise-III data revealed numerous thin, thread-like magnetic substructures embedded within the canopy. Numerical simulations reproduced these threads, showing they consist of magnetic field lines twisted by constant motions at the solar surface.
Tracking Spicules Near the Solar Limb
In separate observations near the visible edge of the sun, the mission mapped spicules. These are jet-like structures extending upward from the solar surface.
The observations tracked how the magnetic field distribution varies with height above the solar limb, offering a clearer picture of quiet-sun atmospheric dynamics.
SCIP Instrument Powers High-Resolution Data
High-resolution data collection relied heavily on the Sunrise Chromospheric Infrared spectroPolarimeter, known as SCIP. Developed under the leadership of the National Astronomical Observatory of Japan, SCIP functioned as one of three specialized instruments on the balloon gondola.
The near-infrared spectropolarimeter allowed researchers to continuously observe magnetic fields stretching from the photosphere up through the chromosphere.
Clues to Solar Atmosphere Heating
Masahito Kubo and fellow researchers detailed these findings in their published study, titled Three-dimensional Magnetic Field Structure of a Quiet-Sun Region Revealed by SUNRISE III/SCIP.
The detailed mapping of these weak magnetic fields offers vital clues for solving long-standing questions regarding how energy moves upward to heat the solar atmosphere.