ABSTRACT
Under quasi-radial interplanetary magnetic fields (IMF), foreshock turbulence can have an impact on the magnetosheath and cusps depending on the location of the quasi-parallel shock. We perform three-dimensional simulations of Earth's dayside magnetosphere using the hybrid code HYPERS, and compare northward and southward quasi-radial IMF configurations. We study the magnetic field configuration, fluctuations in the magnetosheath and the plasma in the regions around the northern cusp. Under northward IMF with Earthward B x , there is a time-varying plasma depletion layer immediately outside the northern cusp. In the southward IMF case, the impact of foreshock turbulence and high-speed jets, together with magnetopause reconnection, can lead to strong density enhancements in the cusp.
ABSTRACT
Formation, spontaneous spin-up, and stability of θ-pinch formed field-reversed configurations are studied self-consistently in three dimensions with a multiscale hybrid model that treats all plasma ions as full-orbit collisional macroparticles and the electrons as a massless quasineutral fluid. The end-to-end hybrid simulations reveal poloidal profiles of implosion-driven fast toroidal plasma rotation and demonstrate three well-known discharge regimes as a function of experimental parameters: the decaying stable configuration, the tilt unstable configuration, and the nonlinear evolution of a fast growing tearing mode.
ABSTRACT
By conducting two-dimensional hybrid simulations of an infinitely long field-reversed θ-pinch discharge we discover a new type of plasma rotation, which rapidly develops at the plasma edge in the ion diamagnetic direction due to the self-consistent generation of a Hall-driven radial electric field. This effect is different from the previously identified end-shorting and particle-loss mechanisms. We also demonstrate flutelike perturbations frequently inferred in experiments and show that in the absence of axial contraction effects they may quickly alter the toroidal symmetry of the plasma.
