Hunter Branch Meeting 2025-1

“Our Magnetic Sun”

Dr Hannah Schunker
ARC Future Fellow
School of Information and Physical Sciences
University of Newcastle

Date: Thursday, 20 March 2025, 5.30 pm for 6.00 – 7.00 pm (AEDT)
Venue: NEX, Newcastle Exhibition and Convention Centre, 309 King Street, Newcastle West, NSW
Registration: Please register by 19 March 2025 at 2.00 pm.
Entry: Members, $15; Non-members, $25; Students, $5
All are welcome

Please click here to register

Summary: The Sun is a magnetic star, with its magnetic field driving a wide range of phenomena, from dark sunspots on the surface to large explosions of energy in the outer atmosphere. Generated by the motion of electrically conductive plasma within the Sun’s interior, the magnetic activity cycle of the Sun peaks every 11 years. One of the key challenges in solar physics is understanding the mechanism of the solar dynamo that generates the solar cycle. Recent advances in numerical simulations, combined with high-resolution observations of the Sun’s surface, are helping to address this question. Furthermore, placing the Sun in the context of other Sun-like stars reveals that its magnetic activity is atypical, offering new insights into stellar dynamo processes. The Sun’s magnetic field is the primary driver of space weather, influencing the solar wind that carries energetic particles outward through the heliosphere. These particles shape space weather phenomena, including auroras, which have recently been visible at latitudes as far from the South Pole as Newcastle as we approach solar maximum. Understanding the magnetic field’s generation and behaviour is critical for improving predictions of space weather events that impact Earth’s technological systems—such as communications, navigation, and defence infrastructure. This research also advances our understanding of space weather dynamics on exoplanets, with implications for the habitability of distant worlds and the potential for life beyond our Solar System.

Hannah Schunker is an ARC Future Fellow in the physics discipline at the University of Newcastle (Australia). Her doctorate was conferred in 2007 from Monash University under the supervision of Professor Paul Cally. She then held research scientist positions at the Max Planck Institute for Solar System Research (Germany) in the Department of Solar and Stellar Interiors under the director Prof. Laurent Gizon. Her overarching science goal is to understand one of the fundamental problems in astrophysics: the solar dynamo. She attacks the problem with a top-down approach from two perspectives: i) using helioseismology to understand the formation mechanism and subsurface structure of magnetic active regions on the Sun, and ii) using asteroseismology to probe the internal dynamics of other stars to exploit the solar-stellar connection. Space weather is entirely driven by the Sun’s magnetic field and therefore, from a practical perspective, her work towards understanding the origin of the Sun’s magnetic activity is critical to making reliable space weather forecasts.

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