Examination of the photospheric magnetic field underlying longitudinally oscillating coronal loops

Longitudinally oscillating coronal loops have been seen in TRACE 171 Angstrom data in many different quiescent active regions. The oscillation is thought to be an example of an outwardly propagating slow magneto-acoustic wave. However, the source of these waves is as yet unknown. In the context of SOHO Joint Observing Program 144, we search for a possible photospheric driver to these waves. We examine the photospheric longitudinal magnetic flux underlying an oscillating loop observed between 1200-1300 UT on June 7th 2001. The field was imaged using the Kanzelhohe Magneto-Optical Filter instrument and the SOHO Michelson Doppler Imager (MDI). The dynamics of the photospheric magnetic field underlying these loops is discussed in the context of possible mechanisms causing the observed coronal oscillations.