THE DAMPING OF COMPRESSIONAL ALFVEN WAVES NEAR MAGNETIC CUSP CONFIGURATIONS

The damping of compressional Alfven waves is studied for magnetic conf igurations that harbor a cusp, i.e., a three-dimensional magnetic null . The objective is to determine the quality factor Q, the ratio of the oscillation frequency to the damping rate. By a numerical solution of the resistive MHD equations in the cusp geometry, it is established t hat the Q is of order In [S], where S is the Lundquist number. The res ult constitutes a generalization of recent findings that show that the Q for two-dimensional magnetic null configurations is of order In [S] , and suggests extremely efficient conversion of Alfvenic wave energy to heat in magnetic wave configurations incorporating null points. Imp lications for coronal heating and magnetospheric cusps are discussed.