Type of Project: Data analysis and numerical modeling

Email: vanballe_at_head.cfa.harvard.edu

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

Background:

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).

Project:

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.

Image:

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)).