  In this study, the properties of wavefunctions of the MHD oscillations for a
single and a system of straight flux tubes are investigated. Magnetic flux
tubes with a straight magnetic field and longitudinal density stratification
were considered in zero-\beta approximation. A single three-dimensional wave
equation (eigen value problem) is solved for longitudinal component of the
perturbed magnetic field using the finite element method (FEM). Wavefunctions
(eigenfunction of wave equation) of the MHD oscillations are categorized into
sausage, kink, helical kink and fluting modes. Concerning the amplitude
location of the waves that arise from the flux tube, those waves are identified
as body, surface, and leaky waves, appeared in the case of both a single and a
system of flux tubes. Exact recognition of the wavefunctions can be used in
coronal seismology and also helps to the future high resolution instruments
that would be designed for studying the properties of the solar loop
oscillations in details.
