Sheared-flow generalization of the Harris sheet

A novel, exact class of solutions to the Vlasov-Maxwell system, with self-g enerated magnetic fields and nonuniform plasma flows, are constructed. It i s shown that a gyrotropic distribution function (independent of gyrophase) does not allow equilibrium shear flow; introduction of agyrotropy is essent ial for the maintenance of spatially nonuniform velocity fields. The new se lf-consistent sheared-flow solutions include the shearless Harris sheet [E. G. Harris, Nuovo Cimento 23, 117 (1962)] solution as a special case. These equilibria are likely to be relevant to a variety of astrophysical flows ( most natural flows are sheared) and to a better understanding of the labora tory phenomena observed, for example, in the device MRX [Magnetic Reconnect ion Experiment, M. Yamada, H. Ji, S. Hsu, T. Carter, R. Kulsrud, N. Bretz, F. Jodes, Y. Ono, and F. Perkins, Phys. Plasmas 4, 1936 (1997)] designed to study magnetic reconnection. (C) 2000 American Institute of Physics. [S107 0-664X(00)03104-9].