Solar Intern Program Project:
 Title: Spectroscopic observations of coronal mass ejections

Type of Project: Data Analysis

Skills/Interest Required: Interest in analyzing imaging and spectral data obtained by space missions. No advanced programming skills required.

Mentor: Dr. Hui Tian and Mr. Sean McKillop



Coronal mass ejections (CMEs) are large-scale solar mass eruptions which can potentially cause damage to high-tech systems. Using mainly white-light coronagraphs, observations of CMEs are now made routinely both on the ground and in space. Spectroscopic observations of solar emission lines could provide valuable information on the thermal properties and dynamics of CMEs. This information can be used to constrain CME models and thus improve the accuracy of the prediction of CME arrival time at the Earth.


The project will mainly involve analysis of the spectral line profiles obtained by NASA's IRIS mission, which will be launched in early 2013. The full-disk images taken by the AIA instrument onboard NASAs SDO mission will also be used to identify CMEs and associated phenomena such as solar flares and coronal dimmings. The student will mainly study line profiles during various stages of CMEs and investigate which types of motion are shaping these line profiles. The student will also conduct density and temperature diagnostics for various parts of the CMEs. The student will learn about CME processes and the technique of solar ultra-violet spectroscopy.


Figure 1: Spectral profiles of eight emission lines during CMEs observed by the HINODE/EIS instrument. The diamonds and error bars represent the observed line profiles. The two Gaussian components (two dashed lines) represent the emission of the background corona and the CME ejecta, respectively. Derived spectral line parameters can be used to diagnose the density, temperature and mass of CMEs. The figure is adapted from Tian et al. (2012).


Tian et al., 2012, What can We Learn about Solar Coronal Mass Ejections, Coronal Dimmings, and Extreme-ultraviolet Jets through Spectroscopic Observations? Astrophys. J., 748, 106


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