Title: Magnetic Waves in Solar Coronal Loops|
Type of Project: Data analysis and numerical modeling
Skills/Interest Required: Interest in analysis of space-based observations and use of advanced
modeling techniques. No advanced programming skills required.
Mentor: Dr. Aad van Ballegooijen
The solar corona is heated to temperatures in excess of 1 million
degrees Kelvin (MK). Extreme ultraviolet (EUV) and X-ray observations
of the corona show bright loops that are aligned with the magnetic
field. The precise mechanisms by which the corona is heated are not
yet understood, but magnetic fields are known to play an important
role. One possibility is that the heating is due to the dissipation of
so-called Alfven waves, a type of magnetic waves that travel along
magnetic field lines like waves on a string. The figure below shows
results from a numerical model for the heating of a coronal loop by
Alfven wave turbulence. The average temperature in the loop is about
2.3 MK. The model predicts the existence of small temperature
fluctuations (~0.1 MK) that propagate along the loop at the Alfven
speed (~1000 km/s).
The intern will analyze EUV observations of coronal loops obtained
with the Atmospheric Imager Assembly (AIA) on the Solar Dynamics
Observatory (SDO) satellite. He/she will learn about the physics of
Alfven waves, and will search for observational evidence of
temperature fluctuations along coronal loops. He/she will use existing
software tools to simulate the dynamics of Alfven waves in observed
active regions. The ultimate goal of this project is to determine
whether coronal loops may be heated by Alfven waves.
Results from Alfven wave turbulence model: (a) temperature as function
of time and position along the coronal loop (expressed in terms of the
Alfven travel time). (b) temperature vs. time at one position along
the loop (white line in panel (a)).