Magnetic flux generation and wave emissions during coalescence of magneticislands in pair plasmas

It is shown by using a two-dimensional fully relativistic electromagnetic p article-in-cell code that the tearing instability in a current sheet of pai r plasmas is caused by Landau resonances of both electrons and positrons. S trong magnetic flux can be generated during coalescence of magnetic islands in the nonlinear phase of the tearing instability. The magnetic flux produ ced in an O-type magnetic island is caused by the counterstreaming instabil ity found by Kazimura et al. [Astrophys. J. Lett. 498, L183 (1998); J. Phys . Sec. Jpn. 67, 1079 (1998)]. It is also shown that charge separation with a quadrupolelike structure is generated from the localized strong magnetic flux. During the decay of the quadrupolelike charge structure as well as th e magnetic flux, there appear wave emissions with high-frequency electromag netic waves and Alfven waves as well as Langmuir waves. [S1063-651X(99)0660 7-6].