Echim Marius M, Lemaire Joseph F
Institut d'Aéronomie Spatiale de Belgique, Avenue Circulaire 3, B-1180 Brussels, Belgium.
Phys Rev E Stat Nonlin Soft Matter Phys. 2005 Sep;72(3 Pt 2):036405. doi: 10.1103/PhysRevE.72.036405. Epub 2005 Sep 13.
We consider a two-dimensional (2D) stationary stream of a collisionless plasma injected across an external stationary magnetic field and a background stagnant plasma. The solution is found by solving the Vlasov equation for each species (electrons and protons), the Maxwell-Ampere equation for the magnetic vector potential, and the equation of plasma quasineutrality for the electrostatic potential. The solution of the stationary Vlasov equation is given in terms of two constants of motion and one adiabatic invariant. The partial charge and current densities are given by analytical expressions of the moments of the velocity distribution functions for each particle species. The 2D distribution of the plasma bulk velocity, Vx (y,z), is roughly uniform inside the jet. There is no plasma bulk flow in the direction of the magnetic field. Inside the boundary layer interfacing the jet and the stagnant plasma, the bulk velocity has gradients (i.e., shears) in the direction parallel as well perpendicular to the magnetic field. The parallel component of this gradient, inverted Delta parallel) inverted Delta perpendicular, produces a nonzero electric field component parallel to the magnetic field lines, E.B not equal to 0. The parallel electric field within the transition layer is a basic element allowing plasma elements to be transported across magnetic field lines in astrophysical systems as well as in laboratory experiments where plasmoids are injected across magnetic fields.
我们考虑一种二维（2D）的无碰撞等离子体稳定流，它被注入到一个外部稳定磁场和一个背景静止等离子体中。通过求解每种粒子（电子和质子）的弗拉索夫方程、磁矢势的麦克斯韦 - 安培方程以及静电势的等离子体准中性方程来获得解。静止弗拉索夫方程的解由两个运动常数和一个绝热不变量给出。部分电荷和电流密度由每种粒子速度分布函数矩的解析表达式给出。等离子体整体速度(V_x(y,z))的二维分布在射流内部大致均匀。在磁场方向上没有等离子体整体流动。在连接射流和静止等离子体的边界层内，整体速度在平行于以及垂直于磁场的方向上都有梯度（即剪切）。这个梯度的平行分量(\nabla_{\parallel}\nabla_{\perp})产生一个平行于磁力线的非零电场分量，(\mathbf{E}\cdot\mathbf{B}\neq0)。过渡层内的平行电场是一个基本要素，它使得等离子体元能够在天体物理系统以及在实验室实验（其中等离子体团被注入穿过磁场）中跨越磁力线进行传输。
