the propagation of light, which in concert with the Debye length spatial resolution would require time steps of a small This paper presents a demonstration of the use of a hybrid code to model the Earth's magnetosphere on a global scale. The typical fraction of a microsecond. The electromagnetic code would hybrid code calculates the interaction of fully kinetic ions and a require too many grid points and too many time steps to massless electron fluid with the magnetic field. This code also inbe feasible for large-scale simulations.
cludes a fluid ion component to approximate the cold ionospheric
The hybrid code is offered as a practical compromise.
plasma that spatially overlaps with the discrete particle component.
The hybrid code assumes quasi-neutrality, which elimi-Other innovative features of the code include a numerically generated curvilinear coordinate system and subcycling of the magnetic nates the need to solve the Poisson equation and the attenfield update to the particle push. These innovations allow the code dant constraints on the time step and grid size. The code to accommodate disparate time and distance scales. The demonis nonradiative, so there is no Courant condition with restration is a simulation of the noon meridian plane of the magnetospect to the propagation of light.
sphere. The code exhibits the formation of fast and slow-mode shocks and tearing reconnection at the magnetopause. New results
There have been a variety of one-dimensional hybrid include particle acceleration in the cusp and nearly field aligned codes proposed. For a review see Winske . There are, currents linking the cusp and polar ionosphere. The paper also however, three types of multidimensional hybrid codes. In describes a density depletion instability and measures to avoid one type, proposed by Hewett and Nielson [6], the elecit.