Solar Physics

Instructor: Rui Liu

Email: rliu@ustc.edu.cn

Description

The Sun, the massive object that dominates the solar system and helps to support life on Earth, is also the driver of physical processes in the space environment between the Sun and the Earth, known as space weather. The practical importance of space weather is to mitigate its adverse effects on critical human technological systems, including satellites, their payloads and astronauts, communications, navigations, power grids, etc. This course is focused on the fundamentals as well as the recent progress in solar physics, to prepare graduate students for the space research in general. It includes the basic physical processes governing the formation of the solar interior and atmosphere, the solar magnetic field and configuration, the physical bases of flares and coronal mass ejections, and particle acceleration mechanisms. This introductory course is intended for graduate students and upper-level undergraduate students with academic background in physics/astrophysics. This course spans 40 class hours and merits 2 credits.

Grading

• Homework (25%): to reinforce the understanding of basic physical concepts
• Project (30%): three projects based on data analysis and numerical models to get some hands-on experience.
• Presentation (15%): research articles will be assigned for certain chapters for further readings. Each enrolled student is expected to give one presentation based on, but not limited strictly to, these assigned articles. Each presentation will last about 15 minutes, including 3-min Q&A.
• Final test (20%): an open-book test for physical concepts and intuition.
• Participation (10%): Raise or answer questions in class.

Text Book

“Physics of the Sun: A First Course" by Dermott J. Mullan (CRC Press, 2010)

References

• "The Sun as a Guide to Stellar Physics" edited by Oddbjorn Engvold, Jean-Claude Vial, and Andrew Skumanich, Elsevier, 1st Edition, 2018
• "The Sun: An Introduction" by M. Stix, Springer, 2nd Edition, 2002
• "Solar Astrophysics" by P. V. Foukal, Wiley-VCH, 2nd Edition, 2004
• "Magnetohydrodynamics of the Sun" by E.R. Priest, Cambridge University Press, 2014
• "Physics of the Solar Corona" by M. Aschwanden, Springer, 2006
• "The Solar Corona" by L. Golub and J. Pasachoff, Cambridge University Press, 2nd Edition, 2010
• "The Solar Transition Region" by J. T. Mariska, Cambridge University Press, 1992

Lectures

1. Introduction (Chap 1)
2. Radiation (Chaps 2, 4)
3. Absorption (Chap 3)
4. Photosphere & Convection Zone (Chaps 5, 6, 7)
5. Polytrope (Chap 10)
6. Helioseismology (Chaps 13, 14)
7. Chromosphere & Transition Region (Chap 15)
8. Solar Magnetism (Chap 16)
9. Corona (Chap 17)
10. Solar Eruptions

Projects

1. Line Formation (due on Nov 11)
2. Polytrope (due on Nov 25)
3. Tracing field lines (due on ???)

Presentation

Mid-term presentation (Nov 11)

1. Emilio et al. 2015, ApJ, Measuring the Solar Radius from Space during the 2012 Venus Transit
2. Shapiro et al. 2017, Nature Astronomy, The nature of solar brightness variations
3. Hathaway et al. 2013, Science, Giant Convection Cells Found on the Sun
4. Laurent et al. 2020, Science, Meridional flow in the Sun's convection zone is a single cell in each hemisphere
5. Hotta & Kusano 2021, Nature Astronomy, Solar differential rotation reproduced with high-resolution simulation
6. Ishikawa et al. 2021, Science Advances, Mapping solar magnetic fields from the photosphere to the base of the corona
7. McIntosh et al. 2017, Nature Astronomy, The detection of Rossby-like waves on the Sun
8. Stangalini et al. 2021, Nature Astronomy, Torsional oscillations within a magnetic pore in the solar photosphere
9. Scharmer et al., 2011, Science, Detection of Convective Downflows in a Sunspot Penumbra
10. Grant et al. 2018, Nature Physics, Alfvén wave dissipation in the solar chromosphere
11. Moses et al. 2020, Nature Astronomy, Global helium abundance measurements in the solar corona

Final presentation (Dec ?)

1. Reinhold et al. 2020, Science, The Sun is less active than other solar-like stars
2. Jess et al. 2020, Nature Astronomy, A chromospheric resonance cavity in a sunspot mapped with seismology
3. Mohammad et al. 2021, Nature Astronomy, The origin of reconnection-mediated transient brightenings in the solar transition region
4. Antolin et al. 2021, Nature Astronomy, Reconnection nanojets in the solar corona
5. Mikic et al. 2018, Nature Astronomy, Predicting the corona for the 21 August 2017 total solar eclipse
6. Wright & Drake 2016, Nature, Solar-type dynamo behaviour in fully convective stars without a tachocline
7. Seaton et al. 2021, Nature Astronomy, The Sun's dynamic extended corona observed in extreme ultraviolet
8. Howard et al. 2019, Nature, Near-Sun observations of an F-corona decrease and K-corona fine structure
9. Yang et al. 2020, Science, Global maps of the magnetic field in the solar corona
10. Srivastava et al. 2018, Nature Astronomy, Confined pseudo-shocks as an energy source for the active solar corona
11. Amari et al. 2018, Nature Astronomy, Magnetic cage and rope as the key for solar eruptions
12. Jiang et al. 2021, Nature Astronomy, A fundamental mechanism of solar eruption initiation
13. Kusano et al. 2020, Science, A physics-based method that can predict imminent large solar flares
14. Morosan et al. 2019, Nature Astronomy, Multiple regions of shock-accelerated particles during a solar coronal mass ejection
15. Veronig et al. 2021, Nature Astronomy, Indications of stellar coronal mass ejections through coronal dimmings