  The magnetic components of geodesic acoustic mode (GAM) are analytically
investigated under the gyrokinetic framework with both the m=1 and m=2
harmonics are considered, where m is the poloidal mode number. With the
quasi-neutrality condition and Ampere's law, the amplitudes of various poloidal
magnetic components are derived. It is shown that both m=1 and m=2 magnetic
components exist and are dominated by the cosine and sine components,
respectively. In addition, it is found that the amplitudes of all magnetic
components increase with respect to the ratio of plasma pressure to magnetic
pressure \b{eta} and safety factor q. Most importantly, the amplitude of m=1
magnetic component is significantly enhanced due to the coupling of magnetic
drift frequency with the first and second harmonics of the distribution
functions, thus it can be comparable to that of m=2 magnetic component under
certain conditions.
