Michael Hahn
2012 Regional Award Winner — Post-Doc
Current Position:
Associate Research Scientist
Institution:
Columbia University
Discipline:
Astrophysics & Cosmology
Recognized for: Advancing our knowledge of the extreme temperature of the Sun's corona
Areas of Research Interest and Expertise:Solar physics, especially to determine the sources of coronal heating and the acceleration of the solar wind; plasma waves and damping processes; experimental measurements of atomic properties needed to interpret astrophysical spectra.
Biography:
- PhD, Applied Physics, Columbia University
- BS, Physics, Carnegie Mellon University
Dr. Hahn’s work uses spectroscopy to constrain the mechanisms by which energy is carried into the solar corona (a plasma “atmosphere” around the Sun). His research is integral to solving the coronal heating problem—the question of why the temperature of the Sun’s corona is millions of kelvin higher than that of the surface.
Hahn’s core research projects stem from both observational and laboratory studies, and focus on investigations of the solar corona, solar wind, and atomic physics. His research uses solar observations and builds on knowledge of plasma physics and atomic physics to detect Alfven waves in the solar corona. Hahn was the first to identify that Alfven waves are damped at sufficiently low heights in the solar corona, and carry a substantial fraction of the energy required to power the fast solar wind.
Recently, Dr. Hahn and his collaborators have quantified the amount of energy deposited into coronal holes and found that it is enough to account for the heating. They are now working to determine whether the same heating process is important for other solar structures and also what process causes the waves to be damped.
Dr. Hahn is a Co-Investigator on prestigious grants from the National Science Foundation and the National Aeronautics and Space Administration.
"Ultimately, this kind of research does provide new perspective on space weather, which is known to affect the Earth. Understanding these fundamental processes improves our understanding, of not just the solar corona, but also of space weather."
Key Publications:
- Hahn, M., and Savin, D. W., Observational Quantification of the Energy Dissipated by Alfven Waves in a Polar Coronal Hole: Evidence that Waves Drive the Fast Solar Wind, Astrophys. J. 2013
- Hahn, M., and Savin, D. W., Measurements of Anisotropic Ion Temperatures, Non-thermal Velocities, and Doppler Shifts in a Coronal Hole, Astrophys. J. 2013
- Hahn, M., Landi, E., & Savin, D. W., Evidence of Wave Damping at Low Heights in a Polar Coronal Hole, Astrophys. J. 2012
In the Media:
It's hot... super hot: Finding answers around the sun. Phys.org. November 13, 2013
Waves might heat the solar Atmosphere. Sky & Telescope. July 3, 2012
Speedy tsunami seen on the Sun’s surface. BBC News. July 17, 2013
Astronomers find clues to decades-long coronal heating mystery. Astronomy. October 17, 2013