Stratospheric Balloon Mission Reveals Complex Solar Magnetic Structures

• The SUNRISE III mission utilized a stratospheric balloon to capture high-resolution observations of the Sun's "Quiet Sun" regions.
• By operating at an altitude of 35 km, the mission bypassed atmospheric turbulence, allowing for precise measurement of magnetic field directions and strengths.

Key Findings on Solar Magnetic Fields

• Data from the Sunrise Chromospheric Infrared spectroPolarimeter (SCIP) challenged the traditional model of the chromosphere as a simple canopy of vertical magnetic flux tubes.
• Instead, the canopy is composed of complex magnetic threads approximately 725 km wide, with field strengths fluctuating between 10 and 20 Gauss.
• Researchers identified "opposite-polarity intrusions" (OPIs) within the canopy; simulations (MURaM-ChE) revealed these are actually twisted magnetic flux ropes that likely drive localized energy release and plasma heating through magnetic reconnection.

Measurements of Solar Plasma Jets

• The mission successfully estimated the magnetic field strength of plasma jets emanating from the Sun's poles.
• Magnetic values were measured at 10–20 Gauss in the lower canopy, jumping to approximately 40 Gauss at higher altitudes above the solar limb.
• Scientists believe the higher readings at altitude reflect the thinning of dense "spicules" that obscure direct measurements at lower levels.

Implications for Future Research

• These results underscore the surprising complexity of the Sun's surface and the effectiveness of balloon-based observatories.
• Future missions, including SOLAR-C, will continue to investigate how these small-scale magnetic features and flux ropes contribute to the heating of the solar corona.