SELF-CONSISTENT ELECTROSTATIC POTENTIAL DUE TO TRAPPED PLASMA IN THE MAGNETOSPHERE

A steady state solution for the self-consistent electrostatic potentia l due to a plasma confined in a magnetic flux tube is considered. A st eady state distribution function is constructed for the trapped partic les from the constants of the motion, in the absence of waves and coll isions. Using Liouville's theorem, the particle density along the geom agnetic field is determined and found to depend on the local magnetic field, self-consistent electric potential, and the equatorial plasma d istribution function. A hot anisotropic magnetospheric plasma in stead y state is modeled by a bi-Maxwellian at the equator. The self-consist ent electric potential along the magnetic field is calculated assuming quasineutrality, and the potential drop is found to be approximately equal to the average kinetic energy of the equatorially trapped plasma . The potential is compared with that obtained by Alfven and Falthamma r [1963].