Thesis (M.Sc.)--Chulalongkorn University, 2005

Groups of magnetic field lines in turbulence fields are considered. We use the two-component model of magnetic turbulence, including the slab and the two-dimensional components following matthaeus et al. (1990). This form of the turbulent field can successfully explain the dropout phenomena of solar energetic particles. We can consider that the solar energetic particles follow the magnetic field lines from the Sun. These magnetic field lines are trapped in the small-scale structures called the "magnetic islands" for a while before diffusing throughout all space. Simulation methods, e.g., the Box-Counting Method, the Anisotropy Method, the Dual Lattice Method, and the Principal Component Method, are developed and used to analyze the data from tracing the magnetic field lines in turbulence fields. We vary the magnetic parameter values, e.g., the fluctuation energy to the mean field energy ratio, the radius of the initial circle, the parallel length scale, and the perpendicular length scale. From the analysis results, we can obtain conditions and length scales over which dropouts can occur.