Computational Model of Energetic Particle Fluxes in the Magnetosphere

1. Computational Model of Energetic Particle Fluxes in the Magnetosphere Yu (Evans) Xiang TJHSST Computer Systems Lab 2005-2006 Mentor: Dr. John Guillory, George Mason University Introduction The Earth's magnetosphere is a region of space dominated by Earth's magnetic fields. Motion of energetic charged particles, such as electrons and protons, in this region is affected mainly by these magnetic fields and the induced electric fields. This project seeks to develop a computational model for co-processing energetic particles in the magnetosphere, which will assist in studying the behavior of charged particles and predicting events affected by particle fluxes in this region of space. Figure 1 Earth’s magnetosphere http://liftoff.msfc.nasa.gov/academy/space/Magnetosphere.GIF Description This computational model uses data about the magnetic and electric fields calculated from available magnetohydrodynamics (MHD) code to move a number of charged particles while neglecting their own fields, energy depositions, and relativistic effects. In regions where the field conditions satisfy certain constraints, such as the conservation of magnetic moment, only the guiding center’s movement will be tracked (the north-south bounce, drift due to crossed electric and magnetic fields, and drift due to magnetic field inhomogeneity). In regions where the approximations of the guiding centers’ motions break down, the fast gyro motion will be calculated at the cost of much higher run time. At each time step, an interpolation routine will use a matrix of field values calculated from the MHD code to compute the magnetic and electric fields. Each particle's trajectory and energy will be updated and recorded. A simple visualization routine is programmed to provide a qualitative graphical display of the data. • Problems • Gathering data from direct observation of particle motion in the magnetosphere is very difficult. • Electronic equipment, such as on satellites and orbiting telescopes, can be damaged by collisions with energetic particles. • Disturbances and particle fluxes in the magnetosphere have direct effects on the ionosphere. • Solutions this project provides that can be used to solve these problems • Creation of software to assist scientists studying energetic particle motion in the magnetosphere. • Prediction of events involving charged particle fluxes in this region of space. • Testing tool for future models of the magnetosphere.