Computing the Magnetic Energy of the Sun's Magnetic Field

Advisor: Dana Longcope

Solar flares occur when a large amount of energy is converted into X-rays, heat and supersonic plasma motion. Prior to the flare this energy is stored as magnetic field filling the atmosphere above sunspots and related features called active regions. The magnetic field can be directly measured only at the lower boundary of the atmosphere - the photosphere. The amount of energy stored above this layer must be calculated by extrapolating the magnetic field upward. Until recently this had to be done without constraint from other data. We now have a technique for introducing a constraint from images made at short wavelengths called extreme ultraviolet (EUV). These images show plasma at one million or more Kelvins - plasma which traces out some of the magnetic field lines in the atmosphere.

In this project the student will trace the magnetic field lines visible in an EUV image, from the SDO spacecraft, and then use these to compute an estimate of the magnetic energy. The SDO spacecraft images 6 different EUV wavelengths to show plasma at temperatures ranging from 1 million to 10 million Kelvins. Repeating the process for each wavelength will help us understand the limitations of this novel energy estimate.

For background on this project from previous REU program, see Mohammed Humed Yusuf's 2009 REU Research Log and Presentation.