Physics projects for Y3 and Y4 students

Project description

Density Diagnostics in the Solar Corona

(supervisor: Youra Taroyan)

Nature of project: data analysis, software

Available to students on full-time physics degree schemes or joint students.

Project description and methodology

The optical radiation from the surface of the Sun or another star is what we see with our eyes. The optical emission in the solar atmosphere (corona) is many orders of magnitude less intense and can only be seen during an eclipse. The first observations of the corona date back to ancient times. The element helium was discovered in the solar corona in the 19th century. Current space missions have the capacity to observe the Sun in many different wavelengths. If we observe the Sun in X-rays, EUV or radio wavelengths, the corona appears bright and highly structured, while the surface becomes almost invisible.Current space borne instruments such as spectrometers can be used to measure intensities and velocities of the plasma at different heights and different temperatures. Density diagnostics are important for understanding the underlying physics of many processes in space plasmas. Such measurements can be done by using ratios of emission lines from particular ions that are sensitive to the electron density. Data from the EUV imaging spectrometer (EIS) onboard the Hinode satellite will be used to infer the plasma density in the lower solar atmosphere.

A successful project will develop beyond the above in one/some of the following directions:
Comparison of the density in different regions of the Sun such as coronal holes and active regions and the corresponding heating requirements.

When considering where to take your project, please bear in mind the time available. It is preferable to do fewer things well than to try many and not get conclusive results on any of them. However, sometimes it is useful to have a couple of strands of investigation in parallel to work on in case delays occur.

Additional scope or challenge if taken as a Year-4 project: The density variation with height will be examined using on-disc or off-limb observations.

Please speak to Youra Taroyan if you consider doing this project.

Initial literature for students:

  1. J. L. Culhane, L. K. Harra, A. M. James et al., The EUV Imaging Spectrometer for Hinode, Solar Physics, Volume 243, page 19, 2007.
  2. M. Aschwanden, Physics of the Solar Corona, An Introduction with Problems and Solutions, Published by Praxis Publishing Ltd., Chichester, UK, and Springer-Verlag Berlin ISBN..3-540-22321-5, 2004
  3. P. R. Young, D. G. Zanna, H. E. Mason, EUV Emission Lines and Diagnostics Observed with Hinode/EIS, Publications of the Astronomical Society of Japan, Volume 59, Issue sp3, Pages S857, 2007

Novelty, degree of difficulty and amount of assistance required

New data will be used. Instructions for the installation of EIS and CHIANTI, data download and analysis will be provided.

Project milestones and deliverables (including timescale)

milestoneto be completed by
Software Installation and data downloadend of October
A brief review of spectroscopy and the observationsChristmas
Data analysis and diagnostics procedureend of February
Interpretation of the resultsEaster